I really liked this one - I haven't looked forward to reading a book this much in a while. It was interesting, it was fun, and it had the exact right pace to keep me interested without making me feel as if the author was just going "And then something happened! And then this other thing happened! And then this! And then that!". At the same time, it had some really nice messages - I liked how Lissa wasn't presented as weak because of her depression, and how the text never shames Rose for being wild and having fun. At the same time, it does show that those choices come with consequences and that being responsible requires sacrifice.
I really enjoyed Lissa and Rose's friendship too - there was teasing, jokes and fights, but there as an underlying devotion the whole time. And, again, it wasn't presented as something perfect - both girls suffered a lot because of their devotion to the other. One of my mother's favorite sayings was "Help shouldn't be given when unasked for", and I think their relationship was a good example of that - they each did things to help one another, but they never actually discussed them - each girl just thought she knew better.
The two relationships were also well done, and I didn't get too many creepy vibes from them. The obvious exception was Christian, but since it was acknowledged and he wasn't shown doing anything wrong or alarming, I was still okay with it.
All in all, it was a really fun book, and I'm only taking a star because it's a bit like popcorn - really enjoyed it while reading it, but I can't say it left a deep impression.