I just made a simple script that will help you to install BitTorrent Sync GUI on Xubuntu 14.04. This script should works on other Ubuntu based Linux as well as Ubuntu 14.04, Pinguy OS 14.04, Elementary OS Luna, Xubuntu 14.04 and some others. Actually this script contains commands to add the repository to your system, update the system and install BitTorrent Sync. Simply as that.
First, download the installation script from this link.
Then, open Terminal and type this command to make it executable and start the automatic installation of BitTorrent Sync GUI on Xubuntu 14.04:
chmod +x bittorrent-sync-install.sh ./bittorrent-sync-install.sh
Follow on screen installation to complete.