AMS: The speed depends on what hardware you're running it on, of course, but my experience of VRPC would say that it isn't much different from using an Iyonix, in general, and that's not on a top end machine (it's a reasonable laptop). Disc access is of course far faster, but most of the time not all that important, because RISC OS doesn't do much disc thrashing.
As for the VA customers apparently vanishing, have you any evidence at all that they have been coaxed over because of it? If they've bought VA, then found Windows better, surely that's RISC OS's and the hardware's fault for not being good enough? RISC OS needs to address these questions if it's to survive, not try to hide away from them and rely on people being ignorant of other things (although peoples' ignorance of computers certainly seems to have helped Microsoft).