Saw this today. Really enjoyed it. Franco, Williams and Weisz were great. I was surprised how much I really liked Franco and Williams in these roles. Finely and China Girl were absolutely adorable and you can't help but care for them. Some amazing effects work combined with great voice acting. The film is beautiful, and while there are a few CGI hiccups, I think the look was strong throughout.
However, Mila Kunis was horrible. Like really, really horrible. She has no presence and it felt like every decision she made with her acting was the wrong one. She was the weakest "evil" supernatural being I have seen in a long time. They should have at least augmented her voice. All I could think was, whiny, evil Meg and I haven't watched Family Guy in a long time. But it also touches on another issue. The sisters don't have a lot of time.
The film was always solid, even great when ever with Oz. But the sisters almost have nothing to grab a hold of when he isn't around. Their entire story is rushed so we could get to Oz's confrontation with them, but the story needed more reason for the change and to establish their characters.
Still what little was there, Weisz used and used well. I like how she was a bully and reacted to the situation as such. She is a threat, but also clearly has fears. Kunis had a bit more, but wasted it completely. She was meant to the very essence of evil. To the point that Evanora was a bit turned off. Instead of enhancing the weaker part like Weisz did, she actually brought it down. Whiny, brat throwing a temper tantrum.