I've used them quite a few times. I've bought monitors, motherboards,processors and the like from vendors on the site. But be forewarned to READ EVERYTHING BEFORE YOU BUY. Some vendors are suspect and are due your close scrutiny on any deals they offer you. I used the anandtech and resellerratings.com when using pricewatch. But I've used them from the begining too so I'm not new to the whole buying OEM parts thing.
Time & Research are your tools, use them.
~wnied~