|From nuts heads going outside the ramp surface, I got too some wheel bites on my Powell BB PF (not on the 95a: just small cuts, but no pieces off). Luckily, it's on the wheel edge, so it's not a problem, wheels still roll smoothly (unlike flat spoting ;-( ....). From concretedisciples forum, I heard it's a known issue with very hard wheels such as the PF.
Tried again the Rainskates yesterday on small ramp, and I'm more and more impressed, pumping is much more efficient. I must find bearings+spacers for the Cortech ;-)