We have a server setup locally that we connect to in order to avoid the potential slowdowns of connecting online all the time. We've had minimal problems with it.
Only semi negative thing to be aware of, but is a very minor issue and can be worked around is that the local copy syncs with the elexio online copy every 30 mins, which will create a bit of delay for people working online or guests connecting online. If trying to update something on the web or app and want it done instantly, can just choose to connect online instead, that option is still there, and make the change.