i saw it last week and loved it, I went prepared for dark psychotic characters since requiem for a dream, still I closed my eyes in some scenes like the Ryder last one for example.
I think Aronofsky is a genious, since the π movie i have loved him, his direction is so fast and all this play with mirrors and mind games, he can transfer deep emotions into an image, when i left the cinema I didnt know what was real ad what not.
Portman and Kunis were amazin and I liked Vincent Cassel role a lot!
about portman doubles from wiki
For certain scenes, American Ballet Theatre soloists Sarah Lane and Maria Riccetto were "dance doubles" for Portman and Kunis respectively. At other times, Kimberly Prosa serves as the body double for Portman. Aronofsky said during filming about Portman's ballet performance, "She was able to pull it off. Except for the wide shots when she has to be en pointe for a real long time, it's Natalie on screen. I haven't used her double a lot."