I agree with
ShannonM - Flatter across the rear for the Rolls is the best way to describe the difference. I've put more miles on Rolls saddles than any other saddle, and have a few Turbos as well. They both feel similar in terms of foam density and leather construction. Rolls leather varies in terms of texture, both came in perforated options, but generally, I find Turbos to be a little less grippy, more slippery. But the main difference I find is that Rolls feel to me more wide and flat in the back and give more sit bone support. Switching from a Rolls to a Turbo, I feel more pressure along the crown or ridge of the saddle.