We have been using Synergy at Queo with ubuntus and a mac. We often have to test our projects in Safari browser and because I work with a Ubuntu machine, to be able to use Safari, I had to either get up and go to the mac desk, or use a VNC connection.
Recently I moved my workstation next to the mac desk and synergy works like a charm. I can use the mac with my own keyboard and mouse and no vnc connect/disconnect overhead. True parallel processing!