What do ballet professionals think of this film?
I'm not a dancer or choreographer, but I think I'd be pretty appalled at the notion that a ballerina has to go crazy or engage in some pretty destructive/self-destructive behavior in order to play the part of the Black Swan. Plenty of dancers play this role all the time without going off the deep end. And those that do go off the deep end (not that I know of any) do so for reasons completely unrelated to the roles they perform.
Also, does a choreographer or ballet master give a leading role to a dancer just because she bites him on the lip? Aren't there more rigorous criteria involved? That seemed to me to be what happened in the film.
So, how do ballet pros feel about all of this?