I installed the full version of Whidbey on my machine and was able to fully compile my projects. I did receive an error in which my PDA device emulator would not install; this could be due to the fact that I have a prior PDA emulator, which was installed with VS2003.
I still have VS 2003 installed as well with no problems. Whidbey is slightly sluggish in performance and there are some user interface glitches, but the overall experience is a net positive.
I am looking forward to taking advantage of new IDE and Debugger features. If I am able to work on VS 2005 after a month with no issues, I will start utilizing language enhancements that may make it difficult to go back to VS 2003, if I decide to ship earlier that the Whidbey ship date.
I did discovered one breaking behavior. ResourceManager.GetObject returns an UnmanagedMemoryStream where before it would return a ManagedStream. I created a Compatibility class to deal with any breaking behavior and a new conditional value VS2003 to handle back compilations.