I have been having problems with synergy client (synergyc) since upgrading to hardy. The mouse and keyboard stutter, at what seems random intervals. There is a bug filed, and the current work around is to run synergyc as root.
I normally have an icon short cut to synergyc on my toolbar. I changed this to run sudo synergyc, not forgetting to change the run type from Application to Application in Terminal so you can enter the root password when prompted. The terminal window disappears after entering the password so it’s not a very irritating workaround.