I liked it quite a bit better than i was originally expecting, mainly because my initial impression was that they were going to try and shoehorn a sympathetic version of Maleficent into the original Disney Sleeping Beauty story. Instead they told an entirely new story in which Maleficent is a (mostly) sympathetic character. Although the story is certainly close enough that you could argue that the animated version is the same story after passing through the distortion of hundreds of years as a folk tale.
From what i understand some people who were huge Maleficent fans before this feel like she was cheapened by this movie or something along those lines. Since i wasn't a fan of her in particular before this however i feel that a more realistic character development beats out having her as an unadulterated bad guy.
There's only two little spoilery things i have to say...
First is that all of us were expecting the "twist" with the "true love's kiss." Perhaps if this movie had come out before Frozen it would have been surprising, but definitely not now. I did still _like_ the twist, but it was certainly no surprise. I did also like the fact that the Prince made at least a token protest about Beauty being, you know, asleep and not consenting and all before letting himself get railroaded by the faeries.
Second, i like to believe that sometime after the end of the movie Maleficent hooks up with Raven Boy. Avalyn and inkbot both said they didn't see it, and something about Maleficent not needing a man anymore. I certainly agree that she doesn't _need_ a man. And i also think it's good that they didn't feel compelled to tie Maleficent's happy ending up with getting a guy. However they did say her heart was healed at the end, and she and Raven Boy had such a great Dom/sub thing going on that i really like to imagine that got developed further at some point :)