The only 3D gaming experience that i have is with my 3DS. It doesn't really affect gameplay that much, it's just a gimmick. And sometimes it becomes annoying, because if you don't keep the 3DS at the same position you will lose the 3D effect and get duplicated and blurry images.
If you've got Mario Kart 7, try putting it in first-person view. You can still steer with the Circle Pad, and it actually does affect gameplay.
-You can't see as much of the course from the angle change, making Rainbow Road a harrowing experience.
-Just wait for someone to use a Blooper. If you thought you couldn't see before.....
And platformers kind of have a slight advantage on the 3DS, I think. I've found that when compared with Super Mario Sunshine (or 64), it's easier to tell where Mario will land in Super Mario 3D Land. And I'm not having to rely on his shadow quite as much.
Edit: But other than that, the 3DS has yet to provide, in my opinion, a truly immersive 3D game.