I had a N3DS, it was my first handheld and it was great! Really good selection of games. My most played were Monster Hunter Generations (which was my introduction to the series) and Fantasy Life - one of my absolute faves, a charming and colorful fantasy adventure with life sim elements. The story is a bit meh but the gameplay loop is incredibly satisfying and there’s nothing else quite like it. I’ve been replaying it on an emulator (rip Yuzu/Citra devs) recently and it’s still a blast.
I’ll be a contrarian and throw in my vote for the second game - it’s rushed and flawed and the asset reuse is blatant to the point of being legendary, but the setting and story are the best and most original of these 3 games. Just being a hero of one single city instead of the entire world is surprisingly refreshing.
In general I’d say that 1 has the best combat/tone, 2 has the best setting/story, 3 has the best characters. I’ve heard that 3 can be quite enjoyable if you pretty much only do the main story and companion quests - but I wouldn’t know, I’m one of the poor fools who got stuck in the Hinterlands, and that mistake + the very underwhelming main story sapped my will to continue playing.