From a functionality perspective, the two services are identical except for a couple of add-on modules like web file viewer. However, on-premise deployments run inside your data center on hardware provided by you. You control and manage all aspects of the service. With private cloud deployments, we create a dedicated, high-availability, setup to run your instance of MangoApps and manage the service for you including data backup, etc. You can choose to have the service as open or as closed to the Internet as you want ( e.g. only available over your VPN setup, available to some IP-ranges or accessible from the internet).