There is slight difference in curriculum for example, PCOM-GA does neuro in first year, while PCOM does neuro in second year.
PCOM-GA carries PCOM name with it so that's a huge advantage. Other than that, not much difference between the two campuses.
I will say one thing though. Compared to other new schools, PCOM-GA has a significant advantage with having PCOM name with it. If you're a PCOM-GA student, you can definitely come up to Philly/PA and do your rotations there and build connections. Yes, PCOM-GA is technically a new school, yet it is using a curriculum model that has been proven from time to time with a vast alumni network so it can be almost considered an established school.
You can't go wrong with attending PCOM-GA though if you're from that area and prefer the more rural setting that PCOM-GA offers than the Philly rural area.