The Ati and other include nvidia support hardware acelerated physics for bullet, and is multiplataform (Xbox360, PS3, Mac, Linux, PC, Android, Iphone), not need to install drivers and appear is the standar for all tool's

I know is a great work to change the physics but 3DGS ever make the support for the more solid options and Bullet is the future ,all support and not limited like physX

Bullet