I just ordered one of these refurbed units from Amazon and I’m impressed. It came in a retail box with all accessories and documentation and not a scratch on it. I’m thinking these are new old stock units direct from Enermax. The build quality is as good as it gets. If you have some P4 machines, particularly emachines or other cheap manufacturers, it would pay to toss the stock PSU and install something like this.
350 watts is actually fine for most machines without a high end graphics card, here is a PSU calculator, check for yourself. The super high wattage on power supplies is mostly a sales gimmick.
Here is the link to the PSU. I also received a refurbed 465 watt unit, but it does not appear to be new. I paid $12 for that one.