I saw it a week ago on opening day here (opened in UK before the USA, ha!). I really liked it. If you haven't seen it, don't read further, but do go.
I saw it in 2D. Tried to keep my expectations in check, which was difficult but I managed. Lots of disappointed reaction here in general. As far as I can tell, some folks were upset that it wasn't more like Alien, while others were upset that it wasn't like Alien enough. I think it works fine on its own and was less interested in it as an origin story for the Alien universe.
Yes, there were some stupid, nonsensical things. Dumping your DNA into a river does not create life [anyone beating off in the shower can breathe a sigh of relief]. Aside from the visuals and the old-school scifi vibe, what I liked most were the ambiguities and the questions (bigger ones sometimes hiding behind the dumber ones, but still).
The best questions boiled down to, essentially, WTF? Even if other/higher beings existed, why do you think finding them would provide any answers? What if the answers aren't what you expect? What if you get hostility? Is Charlize Theron an android?
Noomi Rapace was as Ripley-fierce as we all wanted. Idris Elba was predictably great -- Scott continues to populate the universe with regular folks-at-work and not just the assortment of neurotics or mercury astronauts provided by central casting for many space flicks. The robot was excellently done, although the snide remarks later in the film were a bit overdone. Would have been more menace without them. The relationship ended up nicely complex at the end, though, so all is forgiven.
Overall, it's like a weird and wonderfully nasty remake of Contact.