I use BitTorrent Sync with my FreeNas box. It's absolutely amazing. I am able to completely subvert the cloud and have all my data synced across devices. The mobile app is a user-friendly delight. I was able to share 15 GBs of vacation videos with 10 of my non-techie friends by sending them a read only key to a shared folder. All of them got it right away with no technical questions or issues.
Most importantly, I have all my photos and videos synced as I take them. This means I don't lose precious photos from a trip if my phone accidentally falls in the ocean. My phone, laptop, NAS, iPad, all have my photos backed up providing good data redundancy. No cloud services involved, no risk accidental publishing something private, no risk of an account hack, and no expensive data storage plans.
The only problem is I have to trust BitTorrent's proprietary software to do the heavy lifting for me. This is why I want the SyncThing project to catch up.