I watched the film without having ever read the graphic novel, so I've tried to think about it simply as a film. As such, I prefer V for Vendetta, which covers most of the same points.
Nixon's makeup was awful. The initial shot of Nixon from a distance had the best voice impression, from there it went downhill. Even in 1985 we knew Nixon was much more obscene out of the public eye, so his dialogue was as rubbery as his makeup. This Nixon is still the anti-communist cold warrior of the 1960 election, not the President who went to China and toasted Chou En Lai.
I thought the movie was effective at trying to give the feeling of simultaneity of experience that Dr Manhattan felt, by cutting back and forth in time. It also did acheive the effect of convincing me that anyone with God like powers is going to be aloof and apathetic to the human condition, that vigilantism becomes thrill seeking too easily. The other supers were more then Batman-esque characters. I think the movie is pretty clear that Ozymandias is both super-smart and super-fast, for example. They all can take a lot more punishment than the normal folks they beat up.
I enjoyed Rorshach's voice overs and dialogue, but as I said earlier, preferred V doing the same schtick. So V for Vendetta will remain my favorite Alan Moore adaption for a while. until they make a trilogy out of Lost Girls!