I just went to an IMAX movie, and can't comment on the real3d. Maybe the local theater is real 3d. If so, then I don't see much difference. However, the IMAX required that I keep my head straight up and down, or I would see split images.
The effect seemed nice with a postproduction quality 3d movie, John Carter. I am sure Prometheus will be fine on either versions since it was filmed with proper 3d cameras.
To get more ideas on which one will be better choice you may
click here from the article.