I've just come back from the premiere at the London film festival and I've thoroughly enjoyed, it but before I say anything, do not expect it to be "a mix between V for Vendetta and the Dark knight" which is a complete nonsense I read earlier, it's nothing like it.
In fact, the sci fi element is only a small (albeit crucial) part to the story, most of it taking place in present day London.
It's more of a psychological drama, a bit of a slow starter as well until all the pieces are put together and it starts making sense. To be honest the less you know about the story, the better otherwise it will ruin your enjoyment
The acting is excellent, I would say it really is Eva Green's movie, she shines throughout the movie with a rather difficult role and is absolutely beautiful. Sam Riley and Ryan Philippe are very good too although they have a little less material to play with.
I think it's going to be hard sell as it is unlike anything I have seen, and if they try to market it as an action/sci fi movie, it will be very misleading but I still definitely recommend it if you're looking for something a bit different.