I went to Mercer for undergrad so I'm super familiar with the Macon campus.
Pros:
Campus feel/activities because the medical school is on the undergrad campus (pro for me personally, could be a con for some people)
Campus is constantly upgrading (just built a new science building steps away from the med school building)
Cost of living is lower than in Savannah (I interviewed in Savannah and the current students said most people live in/rent houses, apartments are widely available in Macon)
About 1 1/2 hours from Atlanta (I've made the drive sooo many times, it goes by super quickly)
Cons:
Medical school building is older/not as fancy as Savannah
Not much to do in Macon compared to Savannah (random, but Macon is getting rid of its only Target and that really bums me out lol)
Hospital is farther away than Savannah (hospital is walking distance behind the med school building in Savannah)
No close access to the beach like in Savannah
While at Mercer for undergrad, I 100% thought I'd choose the Savannah campus for med school, but now I'm realizing that the campus feel of Macon is better for me
I'm probably forgetting stuff, so if you (or anyone) have any specific questions about the Macon campus/Macon in general, please feel free to ask