Surprisingly good/the largest case of your mileage may vary ever.
Firstly I'ld like to point out that I'm one of those people who wait to see a movie until its been out for awhile. Why? To read reviews of course, and usually I wouldn't write one of my own.
This movie just because the exception.
Reading the reviews I had expected the movie to be a waste of money and a waste of time. Everyone keeps talking about how the extended plot ruined the point and how the romantic sub plot of the movie made it even worse. I disagree.
The movie first off is absolutely beautiful. It was the main reason I wanted to go see it, the animation is amazing and the character expressions are to die for. Secondly is the actual story which gets a lot of flack. Yes it was expanded, and while the expanded part wasn't in any way epic or a masterpiece it wasn't bad. Most of the light heartedness comes from the fact that this is a childrens movie and was intended for younger audiences. If the movie had been exactly like the book we would have been left with probably the most depressing film of the year (not to mention the shortest). The added content could of used some maturing but it over all want bad. The inserted comedy was actually funny, even the stuff for the kids, and theres plenty of stuff for older people too (just listen to the Onclers song during his heel face turn, it was chalked full of all the excuses a corporate executive makes to rationalize their views).
The music in the movie is also very good except for one or two songs (mostly the opening theme) that make you want to plug your ears. But thankfully most of the sound track is wonderful and well done.
The movie isn't without its flaws though. It could of been more mature or stuck closer to the original story. I could of also dealt without the the stupidity of all the citizens of Thneedville. But overall these things didn't ruin the movie.
In the end I'll say this: I personally enjoyed this movie, it was funny and charming with a good does of heartwarming at the end, and to me it doesn't deserve all the hate its getting. That said its not for everyone. If your a die hard lover of the original story and wont stand for a lighter take on it then this movie really isn't for you.
But really give this movie a chance if your open enough to some changes.
Its not as bad as many people say.