What do you mean by IQ? As far as I'm concerned, it means Intelligence Quotient and refers to a person's level of understanding.
I can't do a like-for-like comparison of the Schneider 28mm lens, as the only Zeiss lens I have of that focal length is the 28-70mm zoom and it would be unfair to compare a zoom against a prime.
The Schneider lens is rare and expensive secondhand as it is a Perspective Control lens. The Zeiss 35mm version is probably rarer still, as the Schneider has adaptors that allow it to fit a range of different camera bodies so more would have been sold. The Zeiss was only available in Contax/Yashica mounts (would there have been a Rollei version?), so you'd had have to be a very keen, and well-heeled, Contax owner to afford one.
I do find that the shift facility of the Super Angulon needs a great deal of bracketing to get a properly exposed image. I really need to carry out some test films to determine by how much the exposure meter settings need to be adjusted to get the correct exposure - they're generally too dark.