In the world of RT, I'd give it 70%. Visually it's very stunning and I thought the CG looked really good blended into the world it was presenting. The story was also good. It's not super complicated but it is your typical "who really is the bad guy" plotline. There were shades of gray so it wasn't completely cookie-cutter. I did find the characters interesting and wouldn't mind seeing more of them if they decided to do a spin off or sequel. I'm not a huge Scarlett Johansson fan but she did an OK job. I've seen bits and pieces of the Japanese anime that it is based on but not enough to spoil this experience so I went in pretty fresh.
This isn't a must see and normally I would recommend to just wait for this on Blu-ray, but the visuals in IMAX 3-D were really good and they did not disappoint.
