BUT BTSync is an Orange to the Apple of Dropbox and company. Dropbox and such is CLOUD BASED. BTSync is DRIVE BASED AKA you can't log onto some web page and get your files.
My Likes:
1) I have 4 work computers 2 personal computers and 2 laptops with BTS and it works great.
2) I just share folders based on my 6+ year old file server structure. All my file are available with whatever file structure I want on any of my devices.
3) Syncing my pictures from my desktop to file server is automatic and FAST on my local server.
4) My mobile devices I can pick and choice what files I want and download into any folder I want. (I have podcast available only on YouTube. I download the audio and store it into my podcast folder. Those files are automatically sync to my podcast program and are avilable. If I have a ton of books I can pick and choice what book and store it into any reader app (Amazon, Google, etc))
5) Super simple sharing of massive video files for editing. I have a friend I help with some video edit and audio processing. I have a raw and a cleaned folder and I just place the finished files in my cleaned folder and they go ONLY to my client's computer directly and not some website. Awesome way is that the raw is read-only on my side and cleaned is read-only on his side. That way it is clear who did what and mistakes (Which always happen) are clearly under the control of each side.