i own a set of sugino 75's and also a pair of shtty RPM cranks that came off my roomie's fuji track.
the RPMs are as stiff as a wet noodle. sugino 75's are much much much stiffer (obviously).
while i was riding, i could see the RPMs flex under pressure. i can see that the Truvativs that come on Pista's may be very similar b/c they are forged similarly.