For your example, I would recommend XData, especially because it's public and you might want to leverage other clients/platforms as well.
RemoteDB is well suited for many users as well, we have a customer that is using it in a place with 300 users, almost 100 simultaneous (note that they are not 100 simultaneous connections to the server, but just 100 desktop workstations working with the software - they might be in idle state).
What I mean is that RemoteDB can be used witih modern Aurelius applications as well. If you have some in-house software, that super high-level security is not a big issue, that will not scale to 5000 users, etc., then you might benefit to have it working right now with RemoteDB (note that RemoteDB is in theory also faster than XData because the traffic is just low-level, binary database data).