I have to admit I'm a little disappointed with the 3DS's game library so far. I only own 4 games for it. By this time in the original DS's life, I had about a dozen games, none of which I regretted buying.
Mario Kart 7 is a lot of fun and I hope I can get around to posting a proper review of it in the next week or so.
But anyway, I bought Mario Tennis Open this passed weekend and thought I would go ahead and talk about my initial impression of it:
I'm really really disappointed that Nintendo still hasn't revisited the "RPG" mode they included in Mario Tennis for Gameboy Color; that was my favourite of the Mario Tennis games for that very reason. I'm not a fan of traditional JRPG's, and Mario Tennis (GBC) was anything but traditional with it and made it a lot of fun. Mario Tennis Open, on the other hand, feels like it was the minimal effort Nintendo could have put into it without having to call it a demo.
There is a Tournament mode which takes some cues from Mario Kart with it being split up into "Mushroom", "Banana", "Fire Flower", etc. tournaments and that's as close as the game gets to a career mode. There are some mini-games which I have yet to try out.
So anyway. as of right now, I'm very underwhelmed with the newest Mario Tennis title.