As far as I'm aware, meshcore has better scaling potential but a more centralized routing model. The same devices can be flashed with the firmware for either, and they operate on the same frequency ranges, so it's easy to switch. The key is what people in your area are already using.

Meshtastic here. There's zero MeshCore activity. I can almost schedule 1-hop 50+ mile Meshtastic chats because people bring their nodes with them on planes. If you really want to spread it in your area, give nodes to children. They'll actually use it because it's fun. Adults are mostly useless.