I do not like much the building files (3dc), but I find very useful the landmarks ones (3dl). Can I use more than one 3dl file for a given country? For example, there is an NQ and an NNG such file for Greece.. If I throw both of them in the building folder, open Primo and look at Settings->Help->About->Content->3d Landmarks, I see both of them. But are they both used, or one prevails over the other, e.g. the newest one? I will "experiment" myself, but does anybody already know?

I don't know exactly about building/landmark files specifically, but if they are like other such map content and there is a 'conflict' between two files, the newer one will be used and the other sort of ignored.