Well, just my $.02 - but just because a washer has good rollover, that in and of itself does not make it a superior cleaning performer against straight vane agitators. Now I agree that the rollover is a bit more exciting to watch, but I have not seen any evidence that suggests rollover automatically = better cleaning. In fact, the Norges of the 1950s always ranked at the top of Consumer Reports washing ability as did the GE Filter Flo's of the later 60's and 70;s with their straight vane agitators. I guess it is a more complex equation - clothing moving through the water, etc...
Case in point, the Kenmore Roto Swirl agitators of the 50's and 60's looked dramatic, but cleaning was always considered average at best.
On the other hand, Frigidaires and the early Philcos (Automagics, Miss Americas) had great rollover and did very well in the cleaning performance department.
Go figure...