I've had it since summer 2007. I just got it back alive, but it does not function correctly. What I did was change the internal Clock Mode to 32 kHz, and then it works as if nothing was wrong. If I use any other mode (44,1 kHz up to 192 kHz), there is no real sound, just white noise and high-pitched hissing that oscillates, and that noise seems to follow the sound that is playing back. Just like when you have a sound file that is played back at a wrong sample rate (which is what lead me to testing the internal clock frequencies), ie. a 48 kHz file that is played at 44,1 kHz - it sounds something like it should, but you can tell there's something very wrong. Except in this case, it is a helluva lot more severe!
I'm not sure if the internal clock means all sounds will now output a maximum of 32/2 = 16 kHz? I think it's just the rate at which the Fireface keeps synchronised. At least from listening to music now, there doesn't seem to be a loss of high frequencies.