Mac, I have a firewire connection to my drive, but I actually revert to USB2 connection mostly, because I find firewire can actually slow things down!
I know on paper the transfer rates SHOULD be much higher, but that doesn't seem to be reflected in the transfer times. It may just be the PCMCIA card I'm using for the firewire that's causing the problem, though it should be fully compliant.
I would suggest, anyway, that the extra money for the firewire connection on the drive, plus the cost of a firewire card for the PC, might not be reflected in a huge improvement in data transfer times.