Note that this is NOT a "please recommend me something" thread. The reason why I ask this is because my brother finally got a 3DS and right now, he's sharing it with us and letting everyone play it.
In my first time using it however, I played Sonic and SEGA All-Stars Racing and Dragon Ball: Origins with it. Honestly, both games felt much better with it compared to the D-Pad. Sure there are several others I've yet to try, but from my impressions, it's going well.