First, I will just say this...I did like the books. *raises shield*
Now, while I did like the books, I can easily see the parallels between this series and the Twilight series (a series that I hate with a passion). Sure, there are differences. Anna has a bit more personality, she's not a (total) puppet, and has stood up to Christian multiple times instead of lying down and taking it. She has a stronger will and is willing to take matters into her own hands.
However, it doesn't stop me from rolling my eyes at most of the crap in the book. There are sex scenes abound in the first book and while there are fewer sex scenes in the later books (thank goodness), they occur in situations that don't make any sense (after giving Christian a haircut, after a car chase, after Christian has nightmare). Plus, like Bella, Anna is initially portrayed as being completely and utterly inexperienced in sexual matters. Am I to believe that this 22 year old single woman has NEVER masturbated? Never watched porn? Really? I don't think so.
And if Christian hadn't gone out of his way to prove his love for Anna multiple times (or had gotten so upset after she left him), then he would be a complete bastard and Anna would have been displaying the biggest case of Stockholm Syndrome since Belle fell in love with the Beast. While Christian's overbearing behavior never reaches Edward-like levels (Christian only states his boundaries and his wants; he's never physically kept Anna from her friends and family and Anna has enough smarts to realize that Christian wouldn't dare), it does reach stalker territory, and in this day and age, people tend to get arrested for the crap Christian pulls.
Once the series actually had a discernible plot (e.g. Who's trying to kill Christian? What happened in past [his mother, Mrs. Robinson, etc]?), then it was a pretty okay read...once you get past the nonsensical sex scenes and the annoying, almost teenage interactions between "Mr. Grey" and "Miss Steele".