I have a 3DS.
Definitely has a great gaming library. Unfortunately they added region lockouts so a lot of the games I would be playing on it aren't available to me.
I don't play it as much as I would otherwise because I find it a little bit uncomfortable to play handheld systems. Playing for more than half an hour or so hurts my neck. What I'd love is for them to come out with a version even larger than 3DSXL that you can set down on a table and play with a full size USB controller. That, or add video output like the PSP had so I can play it on my TV.