Altamont makes some great grips for both of these models. (
Altamont Company) and well priced.
The PT909 is a fantastic pistol, it has a very natural feel to the hand. The PT911 is also an amazing smaller framed choice. I have 2 of the 909 both in stainless and 3 of the 911, 2 in stainless and 1 in the blue finish. I wish I had picked up another in blue before the prices went nuts and the inventory depleted.
As for $600 for a new PT909 in stainless with the pearl grips, my gut tells me that is high, but then everthing in the firearms market is high right now. That being said, it is a discontinued model, a metal and alloy frame, the pearl grip option was not all that common. So if it is with in what you feel is worth buying...then jump on it.