A few months ago, Jered Benoit quit Dropbox:
I own my data, and if I own how they sync, then I don’t have to worry as much about someone letting a three-letter-agency get at my data. Yes, it means that I have the burden of protecting my data and backing it up, but that is a trade off I am willing to make.
This burden is one that you take on when migrating control to something you host or you manage but it means your data is in your hands.
I’ve moved away from a lot of services over the past year but I’m still very ingrained in Dropbox and OK with relying on it in my day-to-day life—for now, at least.
Jered is using BitTorrent Sync to sync files. Sync uses the BitTorrent protocol meaning it’s a distributed platform. Files aren’t ever hosted on any machine but your own, so it’s secure and the only size limitations are those of your local disk space. I’ve played around with Sync and it’s a good option for straight-up, device-to-device sync. For me, it’s not practical to completely leave Dropbox for Sync because Sync doesn’t have the integration to many apps that I use on OS X and iOS.
For secure syncing of files that you don’t want hitting other people’s servers, Sync is great and now an important piece in my tool kit.