I had big problems with the Zalman 400W PSU unit. Not really a problem
with the power supply itself, but more a matter of it not sucking enough
heat out of my case.
Having a few high heat devices (Athlon XP 3000+, Radeon 9800) and not
the greatest case for airflow to start, the system was running at
extremely high temperatures, causing crashes at regular intervals.
You'd probably want to augment the cooling in your case if you go for
this supply; I'm not sure if I'd really consider it a "silent" PSU for
this reason. :P