I don't know about which came first or anything, but I have played Postal 2 and even as a fan of GTA 3 & VC it went beyond my taste, personally. It's also a horribly designed piece of software. It seems every time you move a few yards you have to load another area, and it takes forever.
So I played it once and didn't feel any particular urge to go back to it... *shrugs*
