I agree with this:
If you spend the money to upgrade to VB.NET, well, you just spent a lot of money to stand still. And companies don’t like to spend a lot of money to stand still, so while you’re spending the money, it probably makes sense to consider the alternatives that you can port to that won’t put you at the mercy of a single vendor and won’t be as likely to change arbitrarily in the future. So as soon as people with large code bases start hearing that they’re going to have to work to port their apps from VB to VB.NET with WinForms, and then they start hearing that WinForms isn’t really the future, the future is really this Avalon thing nobody has yet, they start wondering whether it isn’t time to find another development platform.
(From Joel on Software)