None is the "S" category since I don't believe in "perfect" products or services.
A category:
N64 - I placed it at the top due to its amazing quality, iconic 1st party games, and its contributions to overall console and game development. It made strides in things like controller design, compression of software, and utilization of accessories in new ways that impacted gameplay or overall QoL. It also revolutionized the platformer genre and 3D control schemes. I also loved the controller, which is odd, I know. Not without issue (insane game prices, the shoddy build quality of controllers, among others), it still deserves the spot for its impact on both the industry as a whole and on a more personal level for me.
PS1 - I saved up for mine for almost two years, I played it when I visited my cousin. Ridge Racer, Toshinden, FFVII, Metal Gear Solid, Tomb Raider, Crash Bandicoot, Gran Turismo, Resident Evil, Driver, Ape Escape, Twisted Metal, Tony Hawk's Pro Skater. The sheer breadth of the software was immense, unlike anything that came before. It had FMV cutscenes and used the CD-ROM properly, not just as a flimsy add-on or as an afterthought and it even had multi-media capabilities. It also introduced another player in a market that had become hostile for both developers and consumers and worked wonders for pricing and the thinking around publishing and providing developers with tools and support. Iconic, just like the NES and N64. It also signifies the transition from arcades and into the living room, which is also one of the reasons why it went on to sell so well, along with its appeal to a very broad and varied demographic.
PS2 - Carrying the momentum from its predecessor, it provided an insane catalog of games and most major franchises and IPs from the PS1 continued on the PS2. Some would say that the platform had a lot more shovelware, and they would be correct, but the overall quality of its best and most beloved titles was amazing. Doubling as a DVD-player was a nice bonus and Sony made use of their ties to the movie industry in a good way. I have many fond memories of this console, but its astounding success also caused a lot of future issues that I personally have with Sony and the PS brand.
B category:
NES - The lord of consoles to many gamers, including many of my friends. Not just due to some truly amazing games but also for its essential role in reinvigorating the industry as a whole following the massive crash. My sister and I got one for Christmas 1989 and I still remember it, our parents played it too and sometimes invited friends over to play. Nostalgia aside, it had some issues, especially in hindsight, which is why I placed it in the "B" bracket. It kickstarted the mafia-like business model of Nintendo where both developers and retailers got a taste of some pretty indecent policies, many games were of really poor quality, in spite of the famous Seal of Quality, and the breadth of software wasn't as amazing as one would think for a market leader.
PS4 - A massive step up from the PS3, but still not anywhere near PS1 or PS2, in my opinion. What saves it for me is its prominent role in maintaining focus on great single-player experiences in a world gone more and more online. The PS4 also represents some less favorable things, some of which are simply signs of the times we live in and where the market is headed. Franchises like Final Fantasy and Gran Turismo took turns for the decidedly worse for me, and the focus on remakes and remasters is a bit too much. The woeful battery time of the DS4 is another issue, as well as the poor download speed for updates. Overall, it's a good console, but very predictable and "safe". A major plus for streamlining the hardware setup.
Nintendo Switch - It must be somewhat of a thankful task to follow the Wii U; there is only one way to go and that is up. Initially, I wasn't sold on the concept at all, the hybrid function was of no interest since I have no love for handheld gaming at all. But I did buy one, the Switch is a good RPG platform, Octopath Traveler is among the best RPGs I've played in years, and BotW is simply the best Zelda game since OoT. 3D Mario is back in shape as well. Issues for me revolve mainly around the controller and the pricing of software and peripherals. To me, the Joy-con is tiny and borderline useless and the triggers offer poor feedback. Plus for releasing possibly the best controller I've ever owned, minus for pricing it 50% above the competition. UI is sleek and responsive and the cartridges make for lightning-fast loading times and menu swaps - all of which is very welcome in a world where PS and Xbox loading times are getting out of hand.
SNES - I never owned one, but some of my friends did and we played it often after school. The controller was a bit weird to me but it had triggers, which was really cool and useful as well. I wasn't into JRPGs at the time, which means I never got those memories from it, but the SNES was a good multiplayer machine, especially Mario Kart was a blast. Super Mario World was a bit weird for me, I never liked it as well as the NES installments or the following 3D Mario mainline games. It was kind of a niche console where I lived, and things like Amiga, or even keeping your NES, often came before purchasing a SNES. It didn't have the same impact on the industry as the NES either, which is only natural.
SEGA Mega Drive (Genesis) - My neighbor had one, and I borrowed it on many occasions. Sonic was something entirely unique at the time and stood out from other platformers, or games as a whole, with its focus on speed. It made good use of the 16-bit technology for what it was. SEGA had some really cool side-scrolling games and fighting games, the whole concept seemed geared towards a somewhat older audience than Nintendo, which might also be why it never grabbed me as much as some other consoles at the time did.
C category:
Xbox One - there's nothing wrong with it, but also there's nothing unique or exciting about it. Doubly so for someone who never cared all that much for MS and Xbox exclusive franchises. I bought mine mainly for its 4K Blu-ray player, which functions decently. The interface is uninspired and the controller a step down from the brilliant 360 controller. The incessant badgering about online, subscription services and the inflexible always-online functionality are all a real pain and represent a somewhat disrespectful attitude towards consumers, in my opinion. Upsides for me are the initiative for cross-play, crossover, and functionality with Windows and the ease with which developers can make use of the hardware. MS have also been really good at pricing with this platform, with the exception of controllers.
Xbox 360 - Let's address the elephant in the room; this thing was built like flotsam and forced MS into the most costly post-coverage warranty of any consumer electronic product ever. However, the significance of the 360 is not to be dismissed or overlooked. It had a really solid library of games and great 3rd party support, and it provided some much-needed competition for Sony who had gone off-the-rails after the PS2 success. In addition; no one can take away the amazing impact it had on online multiplayer gaming on consoles. For me, on a personal level, I never owned one and never wanted to, the exclusives showed up on PC more often than not, and online multiplayer was (and still is) of little interest to me. The 360 controllers, which I use on the PC even today, are among the best ever made in my opinion. Amazing battery life (I use mine for 30-40 hours before I charge the batteries), great analog sticks and triggers and a pleasing, ergonomic design overall.
SEGA Master System - Perhaps among the most famous "too little, too late" products of our time, it went under the radar when squaring off with the mighty NES. I knew only one person who owned one, but we used it a fair bit. The controllers were so-and-so and the machine itself had a weirdly bulky design, it looked reminiscent of a VHS player. Good games were few and far between and both hardware and software were crippled by staggered launches, leaving strange gaps and uneven graphs in the global market. Perhaps the worst part was SEGA's attitude towards developers, they had witnessed the same crash as Nintendo did, and came up with similar ideas as to how they should build a more sustainable market and industry. Unfortunately, this lead to poor relations with publishers and developers alike and ultimately caused some pretty poor 3rd party support when paired with lackluster hardware sales and segmented launches.
D category:
Xbox - I never understood the appeal of this. MS came from a fully PC background and with what was at that point some pretty narrow Microsoft Game Studios pedigree. I remember the focus being the amazing CPU of the unit, something which interested about 0% of its would-be demographic. Horsepower to take on the juggernaut PS brand proved to be a poor idea. The Xbox had a unique dashboard and PC-like menu and installment system, which was kinda cool, but also allowed for easy pirating and jailbreaking. The controller was bulky and unergonomic, much like the handling of advertisement and release of the machine itself. Support was poor, MS ambitions were a poor fit with current console gaming trends and developer relations were tough to pry from Sony at the time. Establishing a new console brand to pit against two giants was no easy task and the Xbox simply wasn't up to it.
Nintendo Gamecube - "The lunchbox". The color scheme, shape, controllers, ridiculous format choice, and overall marketing of the Gamecube were disastrous, so many poor choices rolled up into one tough-to-sell package. To top it off, it had weaker mainline 1st party titles which had the horrible misfortune of following series best installments on the N64 and it was a lot to live up to. The Gamecube pricing policies are still a good argument against anyone who claims that "mass-market pricing" will lead to mass-market sales, it was ridiculously cheap compared to the competition and throughout the generation, but to no avail. From my perspective, the Gamecube was the first console where Nintendo seemed to forget all their talent, in addition to attempting to merely follow where they had previously been leading. Competing on foreign terms was a terrible idea.
PS3 - Insane pricing, ridiculously contrived architecture, and a piss-poor launch line-up, paired with broken promises and marketing hogwash, make for a tough blow and a lesson learned with the PS3. Despite managing decent lifetime sales, its infancy was a disaster and it underdelivered on almost every possible front. The DS3 was a simple re-skin of the DS2, its lofty 1080p goals with decent frame rates were shot to pieces and developers lent their ear, and resources, to MS at a much higher rate than Sony had prepared for. Extended development time and rising costs also caused problems, both in-house and with 3rd parties, and the installed base ended up at just about 60% of the PS2's when all was said and done. For me, the PS3 was just a series of letdowns and problems, with the exception of a few breakout franchises being born on it.
Nintendo Wii - Another concept that simply never appealed to me, and the product of a company who were fine with temporary success. With a historical rise and equally historical fall for a market leader, it still stands as a wobbly experiment to me and signified a Nintendo which no longer held much interest in me as a customer. There's nothing inherently wrong with that, but for me, it was a massive letdown. Full of impossibly simple-minded software and sporting an unprecedented performance gap, it was a platform dedicated to one purpose; making non-gamers game. Brilliant temporary business, not so brilliant for sustainability. To make matters worse, the pricing of the console itself and its peripherals was bonkers in many regions. For me, buying one Wii-mote + Nunchuk would set me back almost 50% of the cost of the base console, and Nintendo's infamous pricing policy for software once more rebuked me.
SEGA Saturn - The console that showed me that SEGA was out of the game. Clunky and old-fashioned design, both the controllers and console itself, poor support, and frankly absurd pricing. It had virtually no impact at all on the industry or gamers as a group. I played one on only two occasions since it was almost impossible to find in homes, both times were terribly underwhelming experiences. There was simply no room for it at all and it had poor appeal. Its record-breaking short lifecycle was far too long.
F category:
Nintendo Wii U - A terrible concept, even more terribly executed, going from stellar success to immense flop is quite the achievement. I knew from the beginning that I would never want one of these, the ill-conceived controller, lack of features and functionality, and immense reliance on worthless gimmicks were all major turn-offs. Even the name was terrible. I had this to say on the matter about 5-6 months before its release:
https://gamrconnect.vgchartz.com/post.php?id=4619667
SEGA Dreamcast - It was DOA and put out of its misery after only about 3 years. It was cheap and uninspired, SEGA sought to solve issues that were 10 years too late in solving and they offed themselves officially in the hardware space. My cousin actually owned one of these unicorns, it looked like a PS1 Slim and the controller was incredibly clunky and poorly designed, all the cutting of corners were clearly marked all over it. The exclusives, to the extent that such a thing existed, were niched and uninteresting, with the exception of Shenmue, which was amazing. My cousin ended up buying only 4 games for it, there was simply nothing to pick up that the competition couldn't easily match or beat. A truly unworthy end to what was once a force to be reckoned with in the console industry. The only upside is that it allowed SEGA to focus solely on publishing and developing games, and they have some amazing titles under their banner since then.