Personally I dislike OmniMax, or 'IMAX DOME'. Actually 'hate' might be more accurate.
Unless you are sitting in the exact centre of the 'dome' the image is severally distorted. The fact that the screen allows light to pass through it also means some is not all reflected back to the viewer causing a dimmer image. I don't like the color either, washed out compared to other films.
I also don't like that any bright areas show up the frame that holds the screen (looks like dropped ceiling frames!)
The angle to is uncomfortable. It gets back to where you are sitting in the theatre. Too low or high and unless you crank your head around you end up looking at the periphery - not the main subject. That can't be what the director intended.
Ditch the screen, change the aspect back to wide screen and keep the neg size - that would be a better use of the technology.
IMO