I'm running it on a FreeBSD 5.4 box. No problems, runs fast, plays nicely with others.
I run the FAH client under Daemontools. An earlier thread linked some great instructions at bsdguides.org; I didn't take notes, but don't think I changed anything there, and it came right up.
Cool. :-) I'm roughly familiar with Daemontools, although it's been awhile since I've used it. Thanks!