The original New Super Mario Bros. on DS was a good platformer and a great revival of the classic 2D games. Though it was too easy, a little bland, and there was a lot they could have improved upon. I was surprised to see the first sequel appear on Wii instead of the DS (or the eventual 3DS), but I thought it would be about the same quality as the first. I was thankfully wrong about that.
Don't get me wrong, I did like the first game but I loved New Super Bros. Wii. It had such a variety of levels, proved to be a challenge in the later levels (though not terribly difficult), and had levels almost as fun as Super Mario Bros. 3 or Super Mario World. I have yet to play either the 3DS or WiiU sequel, but I will.