I liked it. I only watched it in 2D, but I thought it looked great. Regarding characters/actors, I thought Franco did fine as the Wizard. He didn't take himself too seriously, yet he didn't mock or sneer at the role either. My only quibble with his character was that he took coming to Oz all a bit too much in stride.
I liked all the witches. Someone should hire Rachel Weisz for the next Star Wars film because no one has thrown lighting better since Palpatine. She would make a great Sith Lord. I liked Mila Kunis though the makeup didn't quite work for me, and her role as the Wicked Witch was iffy at times. However, someone already pointed out that she nailed the cackle and when she bit into the role she did a good job. I don't think the film did a good enough job of setting up her up as the green Wicked Witch or explaining why she turned green. I'm assuming it was green with envy. But that led me to another question, after seeing Rachel's transformation, if the monstrous versions of both witches were their true forms. But if that was so, why would Weisz have been shocked by Kunis's green appearance? I did like how the movie added a sense of tragedy to Kunis's transformation. Growing up as a kid and watching Wizard of Oz I never would've imagined that I could sympathize with the Wicked Witch, but this film made me do that a little.
Michelle Williams did fine as Glinda. The highlights for characters were China Doll and the monkey, particularly the monkey. Zach Braff nailed the sidekick, comic relief part. I didn't care much for the other Oz characters. Nuck was annoying, Bruce Campbell's makeup too distracting, and Bill Cobb's hair and beard didn't look right. I think that went for most of the mustaches and hairpieces for the Oz denizens. The flying baboons were well done and came across as far more lethal than the ones in the old film. It makes me wonder where were those guys later on.