I've used two TEAC USB floppy drives, and they both copy data under OS X (10.2.6) at about one third the rate of the same device under OS 9. They also take ages to appear on the desktop after they've been inserted.
I chalk some of the general slowness to the USB tech, but the discrepancy between OS 9 and X? Go figure - I only use the things maybe twice a year though, so I'm not bothered. I remember floppy disk copying being faster under an earlier version of X ... maybe 10.2.4? OT, but If anyone is looking for an update on the most recent developer build of Panther, there's a cool thread in the AppleInsider OSX forum (which seems to be down at the moment) covering it. Native Exchange support in Mail and the Address book was touted at one of the new features ... cool for those who don't want to fork out for or use MS's Entourage Exchange solution (to be released in the US Summer ... sometime). Cheers, Tobes.