If there was ever a golden age of Portable gaming for Nintendo, it would have to be the eras of both the Game Boy Advance and Nintendo DS. Both systems are highly regarded among gamers and Nintendo fans for the robust libraries, superb third party support, and innovative features. The Game Boy Advance, launched in 2001 was the first real successor to the original Game Boy hardware following various revisions and the upgraded half-step that was the Game Boy Color. Basically an enhanced SNES in terms of power, the GBA finally moved the handheld gaming forward out of the simple 8-bit realms of past Game Boy systems, in favor gameplay and visuals that were a little more contemporary. Filled with SNES ports, RPGs, Mode 7 racers, Platformers, sports, etc. The Game Boy Advance was a 2D powerhouse at the time. It also boasted some important innovations for Nintendo handhelds such as its link cable now supporting up to 4 players, a multi-boot function that allowed supported games to have multiplayer off of one game cartridge, and connectivity to Nintendo's home console at the time, the Nintendo GameCube.

If the Game Boy Advance perfected was a handheld game console could do, then the Nintendo DS completely upended it. Released in 2004, the DS was initially positioned as a "third pillar" of Nintendo's product line, it ultimately became Nintendo's flagship handheld hardware brand for the next 14 years, replacing the Game Boy line. DS was a radical departure from previous handheld hardware, boasting two screens, touch input, full 3D, a microphone, and wireless connectivity, including local connection with up to 16 systems, and Wi-fi support which was a big deal at the time. Though it faced uncertainty and a sluggish start against Sony's newly minted PlayStation Portable, the DS eventually prevailed at over 152 million units sold, making it the second best selling game system of all time behind the PlayStation 2.

Between the hardware, library, and impact of these two consoles, which was your favorite?

I have to go with the DS. Like you said the GBA just had so many SNES ports that just played better on an actual SNES.

Between the two - DS.

Although the GBA had a better library of games third party wise - first party on the DS was pretty damn good and the third party wasnt too bad.

Also b/c with GBA games on DS.

There were a lot of SNES ports on GBA true, but I think it had just as many original games and more contemporary ports to balance it out as well. Stuff like Golden Sun, Metroid Fusion, the Fire Emblem and Advance Wars games, the three F-Zero games, FF Tactics Advance, Advance Wars 1+2, Mega Man Zero series and Battle Network, Kirby and the Amazing Mirror. There was still plenty of non-SNES stuff on the GBA.

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I always heard the opposite for DS. Some people felt the Nintendo support on it kinda sucked compared to the third party stuff.

I can see where they were coming from in terms of the core Nintendo series. Super Mario 64 DS was a solid remake gimped by a lack of a traditional analog control, the touch based Zelda games weren't for everyone, Golden Sun Dark Dawn dissapointed, Metroid Prime Hunters was great shooter but also wasn't a proper Metroid either. Star Fox was kinda lacking, No F-Zero, no new Fire Emblem (just remakes), No 2D Metroid, and NSMB got old quickly due to the stagnation of its sequels.

However, I think first party on the DS makes up for it with a slew of New IP from Nintendo like Nintendogs, Brain Age, Style Savvy, and Ouendan/EBA, etc. and Experimental takes on established franchises like Kirby Canvas Curse, Super Princess Peach, and Advance Wars: Days of Ruin. But I think the GBA had overall better quality on the Nintendo side.

For third party support, I'd say it's an even match up between GBA and DS. Both had the best third party support on a Nintendo system for their time since the SNES (at least until the Switch), and some DS fans will argue that third parties often upstaged Nintendo themselves on the console (which is typically unheard of). But for every notable third party franchise the GBA had, the DS had at least one that could match it. I'd give a slight edge to the DS, but both were very strong in this category.

When I think of GBA I just think of a bunch of licensed cartoon games. I know it had more legit games even a ZOE spinoff but man just kinda felt if not into Nintendo's re-releases of SNES games or Spongebob it was slim pickens. DS had a lot of crap on it but also was loaded with RPGs and those DQ remakes.  SMT. A lot of cool stuff. Felt easier to go to a store and find something neat where GBA, Again I know it had good stuff but it was much tougher to find to me. 95% of what was in any Gamestop at the time I went to was licensed shit.

Since the DS (prior to DSi at least) can play GBA games, I'll have to give it to the DS.

In fact, I only still have a GBA due to the Gamecube integration in some titles, other than those I play them on the DS

Both were pretty stinky. It was novel to play 16 but games on the go, but 16 bit was ancient history by then. The DS was interesting for 3D games but it didn’t do them very well. Mario 64 ds was weird, I did like brain age but that was pretty much the only thing that held my attention for a long period. Metroid was super weak. Phantom Hourglass was alright I guess. Well you could learn Spanish and Japanese on the DS. Ok, DS wins.

DS. Why? Super Mario Bros DS & DS Download Play & Pictochat.
Endless.

I was never a handheld fan so feel free to disregard my opinion.

But I enjoyed Pokemon on GB and GBA, and a few other games. By the time DS came out and the biggest games on DS were.... Pokemon again and like Nintendogs, I was kind of bored.

So overall I had more enjoyment with GBA.