I've been really happy sofar. I haven't finished this project build quite yet but I've been using BTSync installed on my nexus 4 auto-syncing my camera folder to my laptop so every time I take a picture I get a notification saying that a new JPG has been added to the folder (and auto downloads obviously).

In this blog post it sounds like I'll be writing, I'll report on sync speeds using 3 nodes and things like that.

Haven't had an issue with it thus far. It's very good on iOS, and running on a few different devices I've got lying around.