I liked it a lot, but wanted to love it. There were a couple of small missteps in areas like shallow characterization and predictable foreshadowing, but nothing 'deal-breaking'. The visuals were amazing, and the 3D was really well done. It added depth and wasn't gimmicky. It was filmed in 3D and not done in post, so feel confident in seeing it with the additional dimension.
I like how they raised some very large questions about the creation of life. Considering how the first Alien film was essentially 'truckers in space', they made a huge leap into thought-provoking sci-fi here. There apparently is even more depth underneath the surface than I'd originally thought. After you've seen the movie, go HERE to read more ... but don't go now because it's filled with spoilers.
The film is just over two hours long, but it could've used about 30 more minutes. It was paced really well for about the first 75 minutes, and then goes into a mad dash to the finish line, almost feeling like they were fast-forwarding to hit major plot points. There are two lines spoken by the ship's captain in the last act that explain about 80% of the film. It felt forced, but due to the pacing near the end, they were necessary. I really hope we get an Extended Cut on Blu-Ray.
I wish the characters weren't so cardboard. Every one of them were stereotypes. I understand that it's not "about them" but I think it would've helped my opinion of the movie if I cared more about the decisions they made in the final act. The performances are all good (Rapace and Fassbender being the standouts), but they didn't really 'need' to be.
The score was most effective when it wasn't being used at all. The first Alien film was about tension, and silence. Prometheus is at its best when it follows that model.
My score? 8/10. Definitely worth seeing on the big screen, but don't go in expecting a masterpiece.