Good for you. Go and see it, I'm not telling you not to. I'm sure there are millions of others who will go and see it too (and love it), but this is just my opinion.
I never felt any connection of the characters. I didn't care who won, who died, who survived. I thought the film (as did the novel) raised many important and topics but never really got below the surface of any of them. I thought the script was, in places, trying to be clever but never really SAID anything. Some of V's monologues were like listening to a poor mans Yoda.
I thought some of the casting was a bit off. A great cast, don't get me wrong, but just some of them weren't the right people for the roles they were playing. Also, I'm not saying it should have been (and I didn't want or expect an action movie) but there was very little action in the film as a whole.
Finally, for a film that tackles issues like censorship, terrorism and oppression none of those came across to me. I understood the situations and concepts but they never transferred from the screen so that I could "feel" the characters plight.