This is probably more like 3.5 stars. I liked it well enough but did not find myself enthralled or sneaking off to read another chapter when I should be doing other things. 
 The first third/half of the book was the most enjoyable. I loved Karou with her tattoos and blue hair and her friendship with Zusana and the odd little errands she did for Brimstone. I loved the descriptions of this aspect of her life, the mysterious scary Brimstone and the wonderfully interesting creatures that made her oddball family. I loved the idea of this fantastical world existing just behind a closed door and loved it was set in Prague and not the US. 
 I began to lose a bit of interest when the oh so beautiful angel turned up and in one glance she falls in love without any further explanation required. The 'oh but it was meant to be' plot was predictable and I'd read something pretty similar earlier this year elsewhere. I dont know why YA books have to always go there with this kind of love at first sight crap. It would have been a much more interesting book if she'd gone through the portal and looked for her family and kicked some baddies ass without the second hand love story stuck in the middle. 
 In the books defense the writing was pretty solid and it was lot more enjoyable than the likes of Matched etc where there is nothing interesting at all, but again, I do wonder if Im coming to the end of my tolerance for YA books :(