Had high hopes for BTSync, and we used it for several months on recommendation of a colleague. However, we found it was fairly buggy in terms of handling files with non-alpha numeric characters in it, and files just wouldn't sync. We suspect it might have been a rogue path parser for .SyncIgnore, not following unix file conventions (we were using it on OSX and Linux), but recently moved over to AeroFS and haven't had a problem since.