I will say this - IF the airport is not finished next time I go, I will do everything in my power to fly directly into Brac and do customs there - when we flew from Brac back to GCM the customs lines were out the door - and there was not good signage about what to do/where to go - lucky my husband and I are fairly familiar travellers and knew that we did not have to go through customs again as we had not left the country of Cayman Islands - we were 'in transit' -
leaving was a breeze - customs in ATL was awful
there are very few comforts inside the GCM airport at present - even less than compared to how it was before construction started - there were at least a few shops in the terminal
Do you have the mobile passport app for your phone? It makes going through customs almost as fast as having Global Entry.