Vidya Balan plays Silk as steamy, sultry and sensual with gay abandon and gusto, something i can't think any of today's or yesterday's actors having the guts to do. In fact, it is only because of her that the movie is even worth watching. It's a must watch simply because of her performance which is as lewd and raunchy as can be, yet you respect her for what she has managed to do and become for this movie.
PS: I don't have a problem with the acting of any of the other characters either; they are all good. But something in the movie is amiss. I can't really point it out, but that something could have definitely made this a much better movie.