Easily the Switch, with its library and what it's manage to achieve with much weaker hardware.

At this point, I'd go with XBone. If you had asked me a year or so back, I'd have said PS4. I don't think there's any arguing with PS4s exclusives this gen. They're far superior to XB, and arguably better than Switch. I currently play most multiplats on my PS4 Pro, and I love it. But, Gamepass has really revolutionized gaming. I'm finding games that I like, but would never have seriously considered if they weren't included in my subscription. Also, I much prefer the XB controller, and I appreciate that they offer upgraded versions of it with the Elites. MS has continuously improved the UI (though the constant changes were annoying for a while, they seem to have finally settled on something good), which has improved the overall experience. In other words, I feel like the XB falling behind early in the generation has driven MS to push things forward, and they have really delivered. PS4 just stayed the same, and was passed by.

Switch is also a great system. I enjoy the portable nature, and of course I like many of the Ninty exclusives. But, the lack of current AAA ports just means it can't be a primary system in my eyes.

In many ways, I'd say this has been a pretty great generation for gaming. I have all the current systems, and I've had lots of fun with all of them. The first few years were nothing special. The Wii U was disappointing in some ways, and the XBone nonsense in the first year or two.... I think this lack of real competition for PS4 caused Sony to stagnate, and MS and Ninty were just playing catchup. But, now, I feel like things are really moving forward, driven largely by MS, but also by Ninty trying new things. I hope Sony feels the pressure and starts doing something to move their ecosystem forward as well.

I should mention that bringing VR to consoles with PSVR was huge, in many respects.  That is a big innovation on Sony's part.  Before Gamepass, it was probably the most important development in console gaming this generation.   As I mentioned, a year or two back, I had PS at the top of my list.....

Your trying to pin down the Switch as a handheld is where your logic is flawed.  The Switch lives in both home console and portable realms.  Usage statistics have already shown that less than a third of owners use the Switch primarily as a handheld.  And the original Switch at full price constantly sells out of stock before the cheaper Lite version which can't be used as a home console.  There is a reason that scalpers feel comfortable listing the original Switch on Amazon at $100 or more over the MSRP over 3 years after launch.

PS4 won by doing every right (hardware, price, software) while the competition stumbled. It's unfair to say they did "nothing", Sony's first party output has been stellar this generation and it contributed to the success of PS4.

I have already explained it in a different thread, but it seems like it's once again necessary.

Handhelds belong to the portable devices. Portable devices are characterized by

o always offering porable usage

o optional stationary usage. (the system may or may not support stationary usage) 

Home consoles belong to the stationary systems, which are characterized by

o always offering stationary usage

o never offering portable usage.

Switch obviously falls into the former, and therefore is a portable device speciallized in gaming.

Scalpers have nothing to do with it, they are only after what makes them the most money.

Also an individual person distributes his/her time on the switch's game modes (handheld, table top, docked) has no impact on the devices definition.

The device itself establishes them via its hardware, not the other way around. This goes for every device, not just the ones related to gaming.

PS4. For me by far. :)

The quote I was replying to specifically mentioned that the Switch has no competition currently because the Vita was discontinued.  Is it your position then that from March 2017 - March 2019, the Nintendo Switch was in direct competition with the PlayStation Vita?  And not in competition in any way with the PS4 or XBox One, despite sharing software like Skyrim, LA Noire, Doom 2016, Wolfenstein II:  The New Colossus, NBA2K, FIFA, etc.  None of which were released on the Vita.  Meaning every time someone bought one of those titles on Nintendo Switch, they were taking a potential software sale away from the PS4 & XBox One versions, while having no impact whatsoever on Vita software sales.

PC

Best current system is easily the Switch.

Generation 8 was the worst time period for gaming since the Console Market Crash in the 80s.  Every single system, Wii U/XB1/PS4/3DS/Vita, was a massive disappointment.  The PS4 was merely the least crappy system out of 5 crappy systems.  I definitely had a hard time finding games that I wanted to play during this "Generation of Suck".

Then the Switch comes along, and it's like an Oasis to a guy who is about to die of thirst in the desert.  Breath of the Wild is the Zelda game I waited 25 years for, and that began a new great era for games.  The NES is the system that I've ever owned the most games for, but at the rate I'm buying games I might end up with more on the Switch.  Switch is my favorite system after the NES, and come to think of it, both came after huge dry spells in gaming.  Perhaps I appreciate these systems more because of the dry spell.

Seems you're looking at this a bit too subjective - PS4 offered pretty descent hardware, VR and quite big library of good games, both 1st and 3rd party (though, admittedly, I don't like most of Sony's 1st party offerings). For me BotW was most dissapointing 3D Zelda (apart from MM), but I can't really give negative points to Switch for that.

As for 8th gen - really depends what games you like. Personally, given that CRPG renaissance happened, I'm more than happy with it.