Although i HATE the Mac OS, I think Apple computers are much better built hardware wise then most any factory pc.
Other then the XPS, which i cant even say if its good or not, but its hardware setup sounds good, Dell computers reek. Especially the Optiplex series. Perhaps the worst combo of hardware used. And right now im pointing fingers at the Optiplex GX280. 2m 47sec to complete pi? Damn, thats one slow computer, considering it has a P4 Prescott 2.8ghz/800mhz bus with HT. That and some of them actually have dual channel ram, some dont, some are normal SDR modules while others are dual channel DDR. Whats up with that? Same exact models, but with different memory set ups.
Which now that i think of it, wouldnt they need to have different mobos too if some had DDR dual channel and some had SDR? I dont think iv ever seen a mobo with SDR slots that has dual channel support.