So, yeah, I'm vaguely aware of the book's actual content. Wife listened to the audio version once and compared it to the same experience I have get watching "so-bad-it's-good" movies. So we both went in hoping for some good laughs if nothing else. Here goes:
The Good
The soundtrack is the second best thing about this. Danny Elfman can be annoying but this was a deliberately mild and muted score for him. The RnB and pop songs laced throughout were solid.
The unintentionally funny dialogue. More on this in a bit.
Cinematography was the best thing about the movie. In the hands of someone less interested or invested, the camera would have been in too big a hurry to get back to the "playroom" and such. Instead, the director and DP showed off lots of neat places and non-BDSM toys of the uber-rich.
The Bad
The dialogue. If Hayden Christensen was wooden in the Star Wars Prequels, then Jamie Dornan and Dakota Johnson are an entire redwood forest. Not their fault and from what the wife says, the script improves the book's dialogue but it's still bad.
The "exotic" stuff. Yeah, not so much. Dakota Johnson is pretty and well built in that skinny girl type. Director did a good job of knowing when to lift a leg or block certain parts to secure that R rating. You've seen steamier scenes in 9 and 1/2 Weeks or Basic Instinct. And the S&M scenes range from comical to uncomfortable (which I think was the point).
Verdict
Not as bad as it could have been but there was no way this was going to be good. It will make a ton of $$$$ and they'll do the sequel but I doubt either actor really will want to be known for this once it is all said and done.
Honestly, unless you are just really curious or into some stuff you don't talk about at parties, I recommend skipping this one altogether.