Go and play Mutant Mudds and Pushmo. You'll change your mind.
Also on the topic I play my 3DS all the time. No game that I play a lot sense I've beaten them all, but every once in a while I'll play a little bit of Resident Evil Revelations or Kid Icarus Uprising. I play eShop games periodically as well. Still have to beat Pushmo and Mutant Mudds. (Damn that final stage). I've got Wario Land to beat yet too.
I still use it pretty frequently. In addition to 3DS games, I use it for DS game. I'm getting several DS/3DS games in the last few months of the year, so my 3DS will be used a lot.
I bought it this year in April, so the answer is yes I own Mario Kart 7 and New Super Mario Bros 2 and I play them both. It's too bad for me that Street Pass, eShop and other similiar services are not available in my region, so I guess I didn't have a complete experience with it yet...
I never put my system down! It's because that it's Nintendo's latest handheld and there are still more games coming up. Now I use it to play Wario Land 3 frequently.
I love my 3DS because there's so many great games I have for it, however I try to play as less as possible when I'm at home because I can't bring my Wii on vacation.
I literally play it EVERY day with Animal Crossing: New Leaf even if it's for ten minutes each day, I'm determined to play it every day for a whole year.
I play it often. I not only like 3DS games, because all 3DS Mario games are amazing. Not only that, but it is so much easier to play DS Games on there too because of the stick thingy that moves (analog stick?)