Getting the Unreal Engine 3 on side is a boost for securing the future of the concept. The PhysX chip "upgrades" the physics calculations of multi-core CPUs.
In order to have a more competitive line-up, AGEIA opted to do a die-shrink of the chip from 130nm to 80nm, significantly reducing power consumption, and enabling the chip to to more with less.
As you probably remember, the first prototype boards featured physical support for both PCI and PCIe x1 slots, but in the end, only PCI models came to market, just like Killer-NIC and Creative's X-Fi. Where these three manufacturers missed the boat was the fact that number of PCI slots just kept on decreasing while PCIe cards were as rare as hen's teeth. With the PhysX card occupying the PCIe slot, the enthusiast market will be far more likley to implement Ageia's product in enthusiast computers.
Ageia will also address the notebook market with upcoming PhysX ExpressCard, so expect gaming notebooks to get a good usage of those ExpressCart ports for gaming, instead of card readers or TV tuner cards.
When it comes to GPU-physics, it is still too early to say, but we saw some nice stuff in upcoming mega-hit Crysis.