It is great to look at, of course (it is Tim Burton, after all). And, since it is Tim Burton, the forward momentum is a bit bumpy, but you expect that.
I saw it on DVD, so I can't comment on the 3D, which was one of those "We'll shoot it in 2D and then convert it to 3D later on" deals. To the experts, that's apparently pretty much like shooting a movie in black and white and then colorizing it later.
But the story is good, the contrasts between the regular world and "Underland" are pointed without being telegraphed, and the actors are wonderful, particularly Johnny Depp (who I always like) as the Mad Hatter and Helena Bonham-Carter (who I don't always like) as the Red Queen ("I need a pig here!"). Plus the voice actors, especially Stephen Fry as the Cheshire Cat and Alan Rickman as Absolem the blue caterpillar. The Jabberwocky has very few lines, but they're especially effective because the voice is Christopher Lee's.
I liked Mia Wasikowska as Alice. In a movie like this, being "the normal person" can be a pretty thankless task, and she's rather bland in the early parts. Some critics complained about this, but I think it's deliberate. Alice is not totally engaged for a long time, because she thinks this is all a dream and she'll wake up at some point. But then she realizes that it is real, and what she does will matter a whole lot.
Of course, the story does have the "Is she the real Alice?" thing (in other words, is she the one?), but even so she does what she does by going off of the path that's laid out for her, by doing what she thinks she should be doing.
And, unlike Roger Ebert, I liked the ending. After all, it's almost always a guy who ends up being the champion.