Actually, FW800 is a lot faster on a PC. I have two G-Tech 500GB Q-Drives which have four interfaces: USB, FW400, FW800 and eSATA. I was an eSATA fan, but with a new motherboard, had problems with the drives being recognized when I turned them on. Added a FW800 board and found I consistently had read speeds of 70-75MB/sec. My eSATA achieved 50-60MB/sec, while USB was down around 28MB/sec. (Actually, my new motherboard has a defect, so I only can achieve a max USB speed at the moment of 12MB/sec.) I run Vista Business (32-bit).
So to answer your question, until USB3 is fully implemented, you'll have much faster results with a FW800 reader and UDMA card.
Nemo