about a quarter into it, and the depiction of bdsm is depressing. But expected. There's clearly a fascination with the topic behind the book, and if you're fascinated with a topic that is considered taboo, you'll need an excuse why it's not your fault that you like it.
Unlike you, I don't think there's an issue about consent, per se - Ana is more or less aware what she's agreeing to. But you could (and you do) make the argument that if she were actually informed she'd know that Christian is a horrible caricature of a Dominant. But, again, I don't think the writing comes from a position of knowledge.
All I hope is that if it tickles people's interest in BDSM they do spend some time to learn about it. To its credit, the story tries hard to get the most important point across - you negotiate your needs, and you keep communicating. That should be good enough to keep a new couple from running aground horribly.
Yes, aftercare matters - but it matters most when you push boundaries. I sincerely hope nobody plans to go for a reenactment of the book on a scene-by-scene basis. (No pun intended ;)