One good thing that came out of the disappointment of bittorrent inc is the open source syncthing which I believe was inspired by bittorrent sync's failings.
I wish they would improve the story around the official distributions.
I'm attempting to migrate away from an aging, single user, files-only OwnCloud instance to Syncthing, and the end user client is not nearly as painless. Syncthing distributes CLI binaries for a bunch of platforms, which is great. But there's no unified GUI for end users that's officially sanctioned. Instead, there's a bunch of 3rd party repos that one hopes they can trust. And, glaringly, zero iOS clients. (I'm working around this by adding a WebDAV server to my always-on system, but it's a workaround for sure.)