I will put my disclaimer up now: I just bought 50 shades yesterday... haven't cracked it open. That being said...
I have mixed feelings about it. I bought it because I've been hearing mixed reviews on it and I'm the kind of person who will read something people are iffy about (or if one group i.e. a church tells me not to), that way I can make up my own mind about it. I decided to buy it to help out a fellow fanfic writer (no, never met her, but still, I feel we should band together, never know if one of us is going to get a big break and we can say "I remember her when...")
I am hesitant to read it because of the fact it was a Twilight fanfic. I read twilight as a youth minister (my girls were asking me my faith based thoughts on it, so felt I had to read it in order to answer their questions adequately) and have to say, not very impressed with Twilight in general. Women at work are obsessed about it and now the latest topic of conversation at work is 50 shades, so yeah, will eventually read it (once I get through my other books I'm working on).
I will say this about my coworkers: I have started to get them to read The Hunger Games, and they are loving it, so there's hope yet for them...
My sister in law was reading 50 shades while also reading THG and said "One is a great work of literary fiction, the other is making my ears bleed and my brain explode, guess which is which..." then continued to tell her friends how crap 50 shades was.
I know that was kind of all over the board, but to sum it up: I bought it to support a fanfic writer, and I will read it, though I don't have high hopes...