Q: What is the difference between a PS2 (not Playstation 2) Power Supply and a non-PS2 one?
A: Your question does not make sence. I think you mean PS/2 as in "personal system/2" a forerunner to the ATX standard. So... I guess PS/2 power supplys are ATX? To be honest with you I think the power supply you are looking at is a cheap one. Go for a standard ATX power supply (taking it that you have a ATX computer, which there is a 95% chance you have) made by a decent brand, coolermaster, be quiet, antec...