Having just spent two days mucking around with my new router to get the G4s and G5s to stop beachballing the minute the airport cards were turned on, I'd strongly suggest the edimax usb. I used an edup usb on an iBook G3 800mhz for well over a year and had no issues on an Airport Extreme b/g/n network. In terms of speed, 802.11b is 11 Mbit max and USB 1.1 is 12 Mbit max, so the difference is negligible. You do need to research the particular model with the edups, because while the new chips will be recognised by PPC macs, the drivers are written for Intel only.