I can't comment for the Schumacher cars, but here we have lots of Yokomos and they are considerably faster with big-bore shocks, specially on rutted tracks and flat-landing jumps. It seems that you have best of 2 worlds : better bumps handling and more pack on jumps.
I will get them for my cars for sure.
The 2wd Vs 4wd thing doesn't make sense for me as they have already almost the same weight. Some 2wd are even heavier than most 4wd.