The Oz from the film is a happy place. There is some strife, with the witches, and some elements to be concerned about, but mostly the people are at peace and free to experience their lives. In addition, it is a rural location. Emerald City is the only urban center, and it exists not as a traditional city, but as a busy household in the middle of a field.
Maguire's Oz, however, is much more modern in a sense. There is political and religious strife, and a conflict over individual rights. There is racism and sexism, a conflict with a tyrranical leader, adultery, corruption, and cities with public transportation, bars, and bordellos. The characters have much more depth, and constrast their movie counterparts. Glinda is shallow and vain. Dorothy et al are portrayed as needy, grasping, and of little importance. Elphaba (the wicked witch) is a neglected and tormented child who grows into a bitter and disillusioned rebel and outcast. Unlike the villianous character of the movie, the book portrays her as a tragic hero, trying hard to improve the world around her, but letting her resentment and fear cause her downfall.