The IMAX 3D experience is worth for some initial scenes - ones right after the opening titles - the sprawling and calm lake, roaring waterfalls of murky water. The most breath taking scene is watching the Prometheus ship hung in the middle of space and some time later watching it in the backdrop of the planet and its rings. I would like to watch it again and again. Too bad it only lasts 5-10 seconds in the movie. Also the scenes where the humans and human-made objects are shown besides the gigantic alien structures are also awe-inspiring.
These things are worth a trip to the theatre. But besides that, the story is lame. Characters and actors are good, but their motives and actions could have used more thought. A work of fiction is more appealing if it can be easily extrapolated from the reality we know.