i've never tried it on the PC but i imagine its probably pretty much the same. Speed and sound quality is basically down to your individual computer spec i think, regardless of PC vs Mac; I got a 2 year old eMac G4 with a gig RAM and the standard soundcard. apart from that i just use a basic M-Audio keyboard controller and a bunch of dilapidated other stuff, crappy decks, guitar amps, instruments, mics etc.

recently actually it's been slowing down a bit and having trouble playing tunes- i'm not sure if this is down to filling up my harddrive with crap, or whether my tunes are become more complicated and a burden on the cpu, lots of fx instances etc.

has anyone else encountered problems with cpu usage like this? i've seemed to notice the using the advanced reverb seems to affect it a fair bit.