I just discovered that our MSDN licensing covers Premium, and I installed Professional.
Can I just install Premium over Professional, or do I have to uninstall and reinstall everything? I’d rather not if installing on top of Professional is safe since I have addins and configuration already set up.
I came across the some issue and needed to upgrade from Visual Studio 2010 Professional to Visual Studio 2010 Premium.
I simply installed Visual Studio 2010 Premium over the Visual Studio 2010 Professional version. All worked without issue ;0)
I did need to reinstall my VS add-ins and service packs (such as Silverlight 4 Tools) and point to my original settings file but that was all. Looks like most or all of my extensions remained in place.