It's been a long time since New Super Mario Brothers, for me, so since NSMBWii was more recent, I can only fully compare it to the new game.
The levels are smaller than NSMBW, probably on par with NSMB, but they are creative, with a lot of variety from level to level. The cannon levels are fantastic, and I wish there were more of them. They feel fresh and new, which is the one thing this game really doesn't have much of. It feels like most of the levels are parts from other mario games, mostly 3, world, and the other NSMB games, just mixed in clever, interesting ways.
The ghost houses are excellent, and there are a few surprises there, but there are very few other surprises in the game.
Still, it's really solid, no levels struck me as boring, most of the boss fights are decent, although after you get your first hit on most bosses, you shouldn't get hit again. Not crazy about the last boss, definitely not on par with NSMBwii or Super Mario 3Dland's final bosses.
I prefer NSMB Wii and 3Dland overall, both are more challenging and longer lasting, but it's still much better than the DS game. The (mostly) short stages are really tightly designed and easy to dash through for a replay. I had fun pretty much the whole time, and I have a few stages to unlock and star coins to get still.