The thing that struck me the most about it was how different it was from the stage musical. I mean, it was still recognizable as the same story, but some major plot points were different, and also some songs were left out, some were added, and some were moved to different points in the story. Now, none of that is necessarily a bad thing; while I missed the "Big Dollhouse" number, with the alterations they made there would have been no place to put it. I didn't particularly miss the other songs they left out, and I liked the songs they put in. Also, moving "I Know Where I've Been" so that it's sung during the march rather than after added a gravitas to that scene that brought tears to my eyes, and even now makes me a little misty just thinking about it again.
That said, my main criticism is that it's less cohesive a story than the stage version (I've never seen the original movie, so I can't make a comparison there). The changes that they made to the story and the songs resulted in some songs (not all of them) that didn't really support or advance the story but just seemed to be randomly stuck in, so that it's "story story story--hold on, we've got to sing something--ok, now back to the story." Also, the mercifully brief plot point in which Velma VanTussle is trying to seduce Tracy's dad seemed rather pointless, though admittedly funny. I think it only exists so that, having omitted the story point of Tracy actually getting arrested, they could work in the number "(You're) Timeless to Me", and for that I can forgive anything because I would have been sorely disappointed had that number not been included because it's one of my favorites.
This brings us nicely to the topic of John Travolta in the role of Edna Turnblad. Let me say first of all that he was good. I did have trouble accepting him in the role, but that was less because of any flaws in his performance and more because I had seen the stage musical first, and so I had a very specific concept of the character of Edna Turnblad as portrayed by Harvey Fierstein. John Travolta's interpretation was quite different, which is the filmmakers' prerogative and, ultimately, was one of the strengths of the film. I think the fact that John Travolta was doing his own thing ultimately made it easier to accept him in the role, because if he had tried to copy what Harvey Fierstein had done then it would have just served to underline the fact that it was someone else. It's just that Harvey Fierstein was so consummate in that role that to see anyone else play it caused me some cognitive dissonance, and that cognitive dissonance made it harder to suspend disbelief as far as the man-playing-woman thing. To illustrate my point, try to imagine for a moment Darth Vader as voiced by Gilbert Gottfried; even if the same guy was in the outfit performing the motions (David Prowse, I believe his name is?), you would more than likely say, "Wait, that's not Darth Vader." And that really gets down to the heart of the matter as far as I'm concerned, because John Travolta used a very soft, very feminine voice for the character, and it was well-done, performed consistently, and consistent with the character as he interpreted it, but it wasn't consistent with the sound I had in my head. I do feel confident in saying that had I not seen the stage version first I probably would have had very little trouble accepting John Travolta in that role, although it's impossible to say for certain.
All that said, I really did enjoy it. While I would have loved to have seen more of the original stage players revise their roles, the cast really was excellent. I think they tried to appeal to a wider audience by casting big Hollywood names, which can backfire, but fortunately all the people they got are big names because they're really talented. I adore the girl playing Tracy, Nikki Blonsky, and I like her singing style better than that of Marissa Jaret Winokur, although to be fair, that probably has as much to do with their respective musical direction than their actual singing style. I was a little concerned about Christopher Walken in the role of Wilbur Turnblad because every other role I've ever seen him play has an element of creepiness to it, so I was worried that he would be a little creepy, but he wasn't creepy at all. In fact, he was entirely endearing. (Incidentally, I was bothered slightly by the fact that Tracy had brown eyes and her parents both had blue eyes, because that's genetically impossible. And I was glad that I was bothered by that because it meant I was past the whole man-playing-a-woman thing.) There's probably nothing I can say about the rest of the cast that hasn't already been said, but they're all so good. Queen Latifah, hell yeah!
I'm so glad to see the era of the movie musical be reborn because, while movies are movies and plays are plays, so many people never get a chance to see a Broadway production, and movies are a way to bring Broadway to the people, and I like how recent adaptations of musicals have been able to retain the spirit of a stage production while taking advantage of the resources that a movie has to offer. While making a movie musical based on a stage musical based on a non-musical movie runs the risk of suffering from replicative fading, I also think that it makes sense to use singing and dancing to tell a story about song and dance; the story might indeed be told more effectively. Again, since I've never seen the original movie of Hairspray, I can't say if this is the case, but I've felt it about other musicals based on non-musical source material.