Better yet, I think its better to wait for the next release then update to the previous one. IMO, Fresh releases of Linux esp Fedora tend to be unstable for the first few months after launch. There is usually new technology or new ways of doing common stuff e.g. Sound playback on Fedora 11 which may have a few bugs on release. By the end of the cycle, the OS is usually stable. 

True, Upgrading can result in orphaned packages e.g upgrading from Fedora 13 to Fedora 14 and you can no longer run Gedit as root due to some python package, If u prefer tip top performance, then reinstall