This Physx card worth it?

[H2O Super-6-1]

Hey guys, i was wondering if this is a good buy, I have a ati 4870 and i want the physx and dont have the money for another card and i dont have the extra pci-e card slot ether. so this good?

http://cgi.ebay.com/128MB-BFG-AGEIA-PHYSX-PHYSICS-RENDERING-BFGRPHYSX128P-/170500138345?cmd=ViewItem&pt=PCC_Video_TV_Cards&hash=item27b299a569

[H2O Krevan]

I haven't seen many games with the PhysX ability, apart from Batman: Arkham Asylum.

Also, I thought PhysX was an Nvidia exclusive.