reddit opinion:
"IMAX is superior in sound and picture quality... Ultra AVX has a wider screen compared to imax and regular screening. The resolution is also higher on Ultra AVX compared to regular screening. Dolby Atmos I think is more about the surround sound quality. But from experience and reputation, IMAX is considered better. Also, IMAX has more of a "full screen" aspect ratio, whereas the other two are more "widescreen", which became the standard for movies. But from a film maker's perspective, full screen is actually preferred as you lose a lot of visuals using a wide-screen. Some movies like Zack Snyder's Justice League, used a 4:3 aspect ratio which is designed for IMAX, while most movies nowadays use 16:9 aspect ratio"
