I'm thinking of the 520 watt version for a future folding rig build myself. I know it will be overkill for a Conroe based folding rig, but I will need to get a 24 pin psu for it anyways and you can't argue about their build quality or warrantee length.

BTW, here's a couple more review links to the 620:

Overclockers.com review

PC Perspective review