I really enjoyed it. It is slow moving and its not your run-of-the-mill comic book adventure, but if you are ok with that, it really plays with the notion od "superhero" and what it would be like with real people. Add to that its setting of an alternative history and you have a very unusual mix.
I think its worth going to see for yourself, because there's little else like it out there, so its hard to compare it to something you might know. Personally, i loved the characters and it was their personalities that made it for me.
Don't expect this film to do anything by the book. No clear cuts, no white hat/black hat characters, no traditional story progression.
Do note, though, that it is quite bloody in a few parts and there is a rather explicit sex scene, too. Not what you'd normally expect from a comic book film, so if this sort of thing bothers you, you might not like it.