I've seen two movies at an OmniMax Dome theater (we have one here in Charlotte) - the Rolling Stones Steel Wheel Tour movie and one of the Harry Potters. The Stones wasn't bad because - hey - it was a concert and you really only cared what happened at the center of the screen where Jaggar and Richards were cavorting about anyway. Everything toward the edges was just unfocused crowd shots you didn't care about seeing, for the most part.
But the Harry Potter movie was awful. It was really only properly focused at the center, and grew gradually more distorted as you moved out to the edges. There was a point where it was like looking through a fisheye lens. And even with the powerful IMAX projector the image was still frightfully dim and everything washed out in shadowed scenes. Sound was great though! (as you would expect)
Bottom line: I'll never do it again. Those theaters are fine for the 45 minute long true IMAX nature/space films. They're all wrong for a theatrical presentation, however, IMO.