Benefits In upgrading to .NET

• Leverage the investment of your current legacy VB6 code
• Since March 2008, Microsoft no longer supports VB6 IDE; migrating to .NET gives you a fully-supported development environment with easier deployment (no DLL Hell)
• The best developers want to learn .NET to avoid to become obsolete in the market, and recruiting skilled VB6 developers is more and more difficult and costly
• High operational cost to develop, maintain and enhance the VB6 code
• With .NET, lower TCO with at least 20% increase in productivity
• 3rd party ActiveX controls not always supported under Vista and future versions of Windows
• .NET allows you to easily leverage the full potential of the Internet and state-of-the-art technologies, including 64-bit CPUs and operating systems, web services, modern user interfaces, multithreading, etc.

MSDN: Why upgrading is necessary
MSDN Screen cast: Visual Basic 6 – What next?