Matt and I watched it last weekend. I thought it was phenomenal.
I really like that there was no hero to the story. It really pulls at you. At first you think the girl is the victem, then the guy, then the girl, then the guy, and even at the end you aren't completely sure whether or not she was justified.
I'm in love with Ellen Page (who plays Hayley). She's Canadian, too, if my memory is correct. Stunning performance by both actors.
I was almost crying during the "castration" scene. That was a tough scene to watch, but I think that it was done very tastefully, even though obviously very hard subject matter.
Also, the movie was filmed really well. I especially loved the way the first few scenes were shot, with just the close-ups of their face and subtlety of their emotions and interactions, the way Hayley frowns when asked about the medical book... fantastic. The scene in the parking lot, as well, where he kneels down to kiss her feet. The hollowness of that scene is captured very well.
It's a hard movie to watch in later parts, but I thought it was amazing.