I saw it last night and I really liked it.
I love The Wizard of Oz, but I'm not a superfan. I've seen it a thousand times and it's really one of the best films ever made.
My only complaints are when Oz first lands in Oz, too much gratuitous use of 3D and more obvious when watching it in 2D.
I watched the special features and they actually filmed with a real Marionette doll for China Girls scenes, with the girl doing the voice on-set doing her lines, so Franco and the others were really acting to a real doll ( and holding it).
After the movie I was googling pics of Margaret Hamilton as the Wicked Witch, they really got Mila looking like a younger version of her. The green color is a better match then you think. I loved her performance, I do think she could have turned it up and maybe mimicked the voice a little better. Seeing her fly on the broom with the black smoke gave me chills.
My only question: when Theodora and Oz went through the waterfall to hide from the flying baboon, why didn't she melt?