Syncthing is designed for decentralized syncing, but I've forced it into a hub-and-spoke model by running one instance on a cheap VPS, with my client machines configured to connect to only that with all the discovery/relay features turned off. It's been painless to administer so far - the "server" has been running without restart since I set it up 18 months ago and I've had to fiddle with "client" settings maybe once or twice in that time. Then again, I don't put it under much stress - mostly documents and source code, no multimedia.
