I got one day 1, the blue-green color, along with SSF4 and Pilotwings. About a week or less after that I also picked up Ghost Recon and will likely pick up Bust a Move and Monkey Ball once I see em used.
So the system itself is pretty nice. The top screen you play on is a bit wider and looks really good. Oddly enough I STILL haven't messed with the AR Cards which are apparently cool to see the first few times then you never use em, or the Face raiders game that it comes with, though a lot of people had said it's fun...even if it makes you look stupid while playing, lol.
SSF4 is arguably the best game out of the launch titles, and though it's odd for me to pay money for this game AGAIN I don't regret it as it actually IS really good and looks great on the 3DS. The new 3D-ish diagonal view is kinda a novelty but the normal view with the 3D slider on looks pretty cool I'd say. The one thing that kinda annoys me is that there's a streetpass feature to battle your collected figures with other people's and I have yet to get one battle in...which is annoying cause my figures are uber and I want to see how well they do and how the thing actually works, lol.
Pilotwings is pretty nice, though I haven't played a ton of it. The 3D effect looks really nice on this one and the game overall looks pretty good. It does start getting a bit hard though, and I hear the end ones are pretty insane so I've been taking it slow. Which I guess is a good thing since apparently the game isn't that long either, lol. Still, not that bad of a game though.
Ghost Recon is like that surprisingly good gem out of a lot of the other junk. If I hadn't heard it was basically like Fire Emblem with guns, I prolly woulda never checked it out. There are some different classes with their own abilities and such to make it interesting. If you have or are getting a 3DS and like strategy games you really should check it out.
I'm also wanting to check out/get Bust a Move, Super Monkey Ball, and Samurai Warriors at some point...but find it hard to pay full price for any other games atm. I'll add more to this thread when I check out some more games.