I've been running my own Synapse instance (the server-side part of Matrix) for a few months now, private, just for friends and family.
Server-side set-up and maintenance is a bit finicky but not bad if you are comfortable with Linux server admin-stuff.
Client-side is very polished, although still somewhat unintuitive for non-techie folk, but not horrible and getting better every month.
@ted I like the layout and the functionality, it's very userfriendly. The only downside is a poor Giphy integration. Also I've had a really busy week and I'm noticing that I don't always enjoy the pace of chat vs microblogging.