Yeah, I'd say it's probably the best one. Difficulty ramps up earlier and there's more inventive level designs much earlier on than NSMBW, which didn't hit its stride until the back half of worlds.
As for length, it's decently long if you're trying to get all the Star Coins. I wouldn't say there's a ton of stuff post-game, there's about as much as the Wii one plus one more level, but there's some non-main mode you should check out like Challenge Mode and Boost Rush Mode. Challenge Mode alone will probably end up doubling the total time I've played.
Also Yoshi is my biggest disappointment with this game. The fricking baby Yoshis can be taken between stages but not regular? WTF? That was like my biggest complaint with NSMBW and not only did they not fix it, they stick a middle finger at those who wanted it with the baby Yoshis. I've heard it's because they want to keep things balanced, but the problem with that is pink Yoshi breaks the game much more than normal Yoshi, and baby Yoshis in eat up enemies so much fricking faster. Bleah.
