Caught Prometheus this evening, and I can conclude two things:
1) Ridley Scott should have just said it was a prequel to Alien.
2) Prometheus is an almost excellent SF horror/thriller which unfortunately gets lost up its own ass in the third act.
I had a really good time. Prometheus is fairly creepy, gorgeous to look at it, has some wonderfully tense bits, and is altogether a strong SF film.
However, it's also kind of a mess.
glvalentine has a pretty damning review of the film up, and I have to say I disagree with a lot of it, mostly because a lot of it is minor nitpicking that wouldn't matter especially if the major issues were addressed.
I do however agree with the major issues, particular that while the first three Alien films were especially notable as SF films that balanced the psychosexual horror of the aliens with the actual villainy of the American corporate mindset, Prometheus tries to follow this up and drops the ball all over the place. There's just too much going on in this film from an emotional and character development point of view, and in trying to wrap up all of it, Scott ends up wrapping up none of it, and the film finishes in a muddled puddle.
There is a ton of setup in this movie for a lot of character development which is ultimately useless because there's actually too much of it. Noomi Rapace's character religious views are particularly irritating in this respect. I don't have a problem with her pseudo-ID-stance conflicting with the more traditional religious views of her father, but the implications of how that conflict resolves in the face of the discoveries of the Prometheus is so totally ignored (despite being constantly talked about up until then), that you have to wonder why it was introduced at all.
The psychosexual overtones of the other in this film are also definitely muted compared to the first films. Part of the concept of the alien that was so terrifying was how gender simply did not matter to it. It was alien in truly every sense, despite it's obvious influence as an avatar of (essentially) rape. I'm not going to go into details on this one, but Prometheus tries and fails to strike that same level of truly alien, and it's more than a little irritating.
Along those lines, there is a momentous, horrifying, and maximally squickifying scene topping the second act, and it's completely forgotten/ignored for most of the remaining third of the film despite it being actually fairly important.
I would still recommend this to series completionists, Alien fans, SF fans who appreciate big visuals, and Fassbender groupies (he is genuinely brilliant in this film; he's so brilliant I think they should take his character in Prometheus, his Magneto, his assassin in Haywire, and his Nazi superhuman occultist in Blood Creek, close them in a jar, shake the jar, and make them fight. With Gina Carano reffing), but I'm not sure I would really recommend it beyond those folks.