To be fair, I haven't heard of Dell using the proprietary PSU pinouts--you know, where a standard PSU would immediately fry the board if you didn't re-pin it before installation--in quite a long time.
I still wouldn't buy one, but I've built my own for too long to do otherwise. None of the usual OEMs make anything I'd pay for, outside of some vendors that basically do custom stuff... and I'm too cheap to pay someone else to do what I can do myself. (Gotta justify this huge pile of bits 'n bobs I keep around, y'know!)
Biting the hand that feeds IT
