All I notice is that polys go long when they're dead. That's about it. I've only played with polys, synthetic gut, multis, and poly/synthetic hybrid. Full bed poly is the only one I've had a problem with, though most recently, I've played with the Luxilon 4g successfully. Right now I have one RF97 strung with the 4g and another strung with technifibre duramix hd 1.35 and can't really tell a difference. Maybe you need to get good before you notice.