I really like BitTorrent Sync. It’s a great alternative to Dropbox et al, without having to hand over your unencrypted data to a third party.
Unfortunately, the default configuration in BitTorrent Sync for Mac OS X is somewhat odd. As it turns out, it syncs all of Finder’s meta data. As you can imagine, this means a lot of pointless syncing.
Why these files are listed in there beats me, but after removing them from there, my nodes stopped syncing like crazy all the time.