Ok. I saw it.
First really great SciFi film I have seen in years. I want to talk about it but I am NOT putting spoilers (or near-spoilers) in here.
For those who haven't liked it much...I think I understand. My take on that: this isn't a movie for non-SciFi fans or people who just wanted to see a whole lot more aliens...it actually is science fiction.
You can critique the premise some--particularly how it gets linearly treated--but I just think that is the time constraint of modern film. It is pretty clear that the hope is that a sequel can follow but as a stand-alone SciFi film, that isn't needed to complete the experince given.
For the actors--in some ways they are understated and even a little underplayed but that's because the plot is taking precedence over the characters--which is a rare story telling form in film nowadays. That said, the pertinent characters--particularly, "David" are intriguingly presented.
A good part of the script follows the pattern of previous movies (but not their substance)--I see that not as a weakness but as a nod and needed inclusion for this new story and that's an inclusion Alien fans demanded.
What I loved about this is that while "Alien" is prominent, Prometheus is really a story that is intimately connected but a completely separate story from Alien.
As to "gaping plot holes"...I think that is more attributed to ignorance on the part of the reviewers--especially ones who have had little exposure to science fiction literature. This isn't just a "movie" and it isn't "Alien IV", "V" or "VI" either.
The plot (to me) was quite coherent and engaging. There isn't a scene in the film I could point at and say, "that has no relevance whatsoever". There are nominal sub-stories in it for some of the lesser characters but the real story works very well.
For those saying, "Bollocks!", I suggest first you consider the name of the film, really think about the film's opening scene (which I think is crucial to the plot in a huge way but not explained for you at all) when you reach it's end and acquaint yourself with the film, "Lawrence of Arabia"--in particular, at least know what the film (and the real life story) of it are all about and pay real attention to the dialogue relating to it.
I could get a lot more into specifics but that would be spoilers, so I won't.
If you are "young" in your exposure to classic science fiction, if you like simple stories with the answers stamped simply and evidently in their plots for you or if you came to see hundreds of chest burstings and cocoonings--you might be disappointed. If you really love SciFi, you'll admire a lot of this film. The sequel (assuming we get one) will really reveal if the story is as strong as it can be or if the telling of it is flawed. So far, I think it will be extremely satisfying to see the sequel (barring network executive interference and stupidity) as it will actually be the continuation of an original story and not another, "tack on adventure".
Last point most natural and effective use of 3D I have seen in ANY film...EVER. I appreciated Avatar's visuals but with the exception of a second or two of foreground gravel near the screen's bottom edge in a hurricane looking a little 2D iot was almost perfect.
Totally thumbs up, wipe your mind, forget your expectations, prepare to think and ponder and just experince it. It isn't the edgy and suspenseful "Alien" but it is wonderful as science fiction (excepting stupid things characters must do to make a plot move).
P.S. I saw it on iMax which would be my recommendation if you can manage it.