I've run into problems with other transfer methods with lots of small files, so I usually bundle the data into a monolithic rar file. FTP behaves poorly (not reaching bandwidth available), Http does very well, but I haven't felt like installing a server on all my machines; simple drag and drop over the network is unreliable with large files. This particular transfer was from a Windows 8.1 machine to a Mac Mini with wired connection through my router, maybe the cross-platform difference caused some of the "slowness" (though 1.1 MB/s isn't completely slow). With default buffer sizes, it would transfer quickly for the first few minutes, but then slow down to 600KB/s-1.1MB/s, it seemed that the presence of other network traffic (Netflix, for example) would put BT Sync "off its game". I have had good speeds transferring over the Internet, but on my LAN the only thing that gave me top speeds was changing the buffer sizes. (And my impatience might be a factor, I've noticed lately it seems to take a while for BT Sync to ramp up to speed.)