The only issue is that it is not really an upgrade. If you upgrade to CC 2014, it just installs the new versions of all the apps on your PC and all your previous CC apps is still on. So basically you will have 2 of every application installed. The problem is that if you uninstall CC after installing the latest version, then all your file associations go missing and corrupt. It doesn't update file associations to the latest versions - you have to do this all manually. Real pain!
The new features are amazing though!