I had some of the same problems with a Firepod that I used to have. It worked great for about six months and then the preamps went all to hell.
I now use a MOTU 828mkII and love it. No problems at all.
If you need 8 XLR inputs like the firpod then check out the new MOTU pre* interface that just came out. If it is like motu's other equipment then I'm sure it is worthwhile.
Current Rig : Mac G5, MOTU 828 mkII, Moog Minimoog, Arp Axxe, Korg Poly 61m, Korg Poly-800, Korg Microkorg, Ensoniq ESQ 1, SQ-80, EPS sampler, DX-27, DX-7, Rx-5 drum machine, Alesis HR-16, Boss Dr-55, Synare, PAIA 9700 system, Roland MKS-100,