Rather than just making another film of the books, this one considers what might happen if a grown up Alice returns to Wonderland. As such it takes a while for the film to get going as they reintroduce the child Alice and then go on to set the context of her life at the age of 19.
When wonderland first appears it generally just repeats some of the events of the book, which is a nice tribute, but it's a bit disappointing that they couldn't do anything new with it. However, after a bit it does start moving into new directions and becomes more Alice in Lord of the Rings. It's quite fun from then on played with most of the characters true to their original form, but it does seem a shame that they had to give it quite so much plot, as that's not what the original was renouned for. However, I suppose it is trying to be a Hollywood blockbuster, so it's probably necessary from that point of view.
It's got a strong cast and it shows throughout the film. Given what Johnny Depp is clearly capable of from his previous roles I was expecting a bit more to the Mad Hatter, but the performance is far from being bad. The rest of the cast bring a lot of life to the other characters, particularly Alan Rickman, Stephen Fry and Barbara Windsor, voicing the caterpillar, cheshire cat and dormouse respectively and Matt Lucas as Tweedledee & Tweedledum. However, the film is stolen by Helena Bonham Carter's wonderfully spoiled-childlike red queen.
The 3D is a nice gimic, but after the first few minutes of the film, I found I got used to it and hardly noticed it anymore. The film certainly didn't need it, but it didn't detract either.
All in all, it's a fun film and well worth seeing. The only major criticism would be that it had too much plot, but that's not enough to spoil the film.