I got a 3DS XL for Christmas in 2013, around the time I had finally exhausted my collection of DS games. (The DS dates back to before 2009 when I started my current record-keeping system, but I spent at least 900 hours on 50+ games for that.) The system has seen fairly steady and regular use over the seven years, averaging 4 games each year. I clocked around 425 hours on 29 games for the 3DS, with a heavy emphasis on first-party Nintendo titles. The biggest time-sink was The Alliance Alive, tying Bravely Default at 37 hours.
The lack of Square-Enix support for this system really showed, with the only real representation being the two Bravely titles and the two Theatrhythm games (FF Explorers wasn’t my thing, and despite the improvements from the PS1 version Dragon Quest 7 still became a slog). I lost interest in a bunch of series I’d followed from the DS (Castlevania petered out, Cooking Mama got repetitive, and the aforementioned Dragon Quest issue), though I enjoyed three more Layton games and two more Mario & Luigi games.
I particularly enjoyed that they made three solid Kirby games, plus each major Nintendo series got a 2D-style game that was really good (The Legend of Zelda: A Link Between Worlds, New Super Mario Brothers 2, and Metroid: Samus Returns). Hyrule Warriors Legends also was excellent, as a well-done merging of two series I like.
I suspect I would have played more indie titles on this if I hadn’t been getting them really cheaply in Steam or Android bundles. The fact that I started picking up KEMCO rpgs on my tablet only nine months after I got a 3DS likely scratched a bunch of my jrpg itch and meant I wasn’t using the 3DS eShop. For that matter, I had enough casual games available on Android that I didn’t need to seek out more Puzzle Quest equivalents.
I never really loved the 3D feature; except for a couple of games where it really mattered (Super Mario 3D Land comes to mind), I usually left it turned off. Honestly, both the DS and the 3DS had a lot of features (3D, microphone, gyroscope...heck, even the touchcreen) that only first-party Nintendo titles ever used effectively.
Overall: While a worthwhile system by any accounting with a lot of good material, the lack of support from Square-Enix and the competition from my Android tablet for portable gaming made it lackluster for me compared to the original DS.