It would be great if Plex Sync would display the current transfer speed, or even an estimated time to completion.
I'm traveling in Southeast Asia right now, and I find myself often at the last minute before getting on a plane trying to sync an episode or two. I think in this case, more info would definitely be helpful, as it would allow me to know if I should even bother, move to a different network, switch to cellular data, etc...
The estimated size of the synced content on disk would be great to know as well. While disk space on mobile devices is growing, many still have little storage space, so knowing ahead of time that the selected items will occupy n amount of disk space would be very handy.