We are now working with Visual Studio 2010 on the PPJ Framework and also started using it on some migration projects. Well... Coming from years of Gupta/Centura/Gupta/Unify development I'm pretty sure that VS 2010 is simply in a different league.
The incredible productivity increase that a software shop can gain by simply switching from Team Developer to Visual Studio 2010 is astonishing.
One of the many useful features is the new Extension Manager. It connects directly to the Visual Studio Gallery and allows you to find, download and install extensions to Visual Studio. There are hundreds of them:
http://visualstudiogallery.msdn.microsoft.com/en-us/
This is a screen shot of the Extension Manager. Developing is more of a pleasure with VS 2010, especially when you are used to fight with TD's outdated limitations and all the recently introduced bugs.
Since I have been in the software business (which is many years) I have always adopted the best technology and tools for the job. Sometimes straight assembly is the right fit, some other times C is the right language. There is no one-size-fit-all solution with software. For business applications there is very little doubt for me.
Visual Studio 2010 and .NET will pay back the cost of the conversion from TD in very little time. Once your code is secured in .NET the return on investment curve has changed from downward to upward.
There is truly no good reason to keep valuable code locked in a proprietary and outdated technology. Really.