playstation controller adapter for the PC?

[vexingv]

i'm just about fed up w/ my dual analog firestorm2 that i've already sent back once...was thinking about getting an adapter so that i could use my playstation2 controller on the pc. i found this EMS USB adapter. anyone have any experience with this or any other similar products? how good (or bad) is the software that's used to map the buttons? how's the price? any suggestions/opinions would be great