I've got four Catweasels (one ISA, one Mk3, and two Mk4), and they all work well with standard 3.5" and 5.25" HD floppy drives. Standard is the key. Teac and Sony work well. Avoid mysterious, unmarked generic drives.
The ISA and Mk3 are known to work under Amithlon (at least, I think I remember the ISA card working under Amithlon). The Mk3 and Mk4 work with current versions of WinUAE under Windows. (The ISA might still work with WinUAE as well, but I'm not sure if Toni still has the legacy Catweasel code compiled in.) The Mk3 and Mk4 should also work on any Amiga system that supports m68k OS3 device drivers and OpenPCI.
If you happen to have a working ISA bus on an Amiga, the ISA card might work there, too. I don't know if that's ever actually been tested with the last release of multidisk.device.