For what it's worth, the adapter is 100 percent problem free for me. Going from OS 9 to X, it didn't even say anything - there is no driver, it just looks like a regular KB as far as the computer is concerned.
Only one hitch - holding down keys during boot has no effect, so I have to keep the regular USB KB around as well, in case I need to boot off CD or something. I actually keep both plugged in, since my mom can't use my KB, and occasionally uses my computer.