We have noticed after migrating to Visual Studio 2005 Beta 2 that refactoring was performing terribly bad. It worked much quicker on the November/2004 CTP and we didn't see a reason for it to change so dramatically, until today, when a colleague of mine, intrigued with this problem actually searched the MSDN Product Feedback web site for other complaints about this issue and got the following result:
http://lab.msdn.microsoft.com/productfeedback/viewfeedback.aspx?feedbackid=f17e1c19-54be-4bc6-bc79-1cefdd324c80
It is so disappointing! JetBrains has a much more powerful and performance refactoring solution for IntelliJ IDEA for ages now and they have also ReSharper for Visual Studio .NET 2003 that works really well, so I don't think that it would be such a challenge for the biggest software manufacturer in the world to come up with something as good. The bottom line now is that it renders refactoring nearly useless in Visual Studio 2005, as any project slightly bigger is going to suffer from this bad design.
Let's hope they can do better by the Orcas time-frame.