I really *liked* it, but didn't love it. That said, I did love Leto and to a lesser extent all of the other actors. That said, I'm glad to see Jean-Marc Vallee make an interesting English language film, after being disappointed with his first English film, The Young Victorian (which wasn't bad, but...)
I recommend to anyone his big Quebec breakthrough, C.R.A.Z.Y. a semi autobiographical film about growing up gay and Catholic in Montreal. It's very, very good, and the reason it didn't get more exposure in the US (and, apparently, why it was not chosen as Canada's entry in the Best Foreign Film category of the Oscars that year) was due to the Weinstein Company buying the remake rights, although as of now nothing seems to have been done with them.
I believe Netflix has it with subtitles
here's the trailer they did when it was shown at MOMA
http://www.youtube.com/watch?v=sCvQ2OpCj8A