There was some anxiety for all of us when the language specific Express SKUs (C# Express and VB Express) that NETMF (and Gadgeteer) work with were not going to be supported in VS 2012. We did learn that these 2010 SKUs would be available for some time going forward but that is not forever and it might preclude you from using a favorite new feature in VS2012 as well as the overhead of having two VS versions to work with.
In June, Soma announced plans for Visual Studio Express 2012 for Windows Desktop that could support both C# and VB development (http://blogs.msdn.com/b/visualstudio/archive/2012/06/08/visual-studio-express-2012-for-windows-desktop.aspx). Today that product went live. http://www.microsoft.com/en-us/download/details.aspx?id=34673.
We are in the final stages of version 4.3 of NETMF with release in the near future. This release will work with Visual Studio Express 2012 for Windows Desktop. In addition, we are in the planning stages for .NET Gadgeteer version 4.3 and this version will also support that Express edition. We don’t have a firm release target for that at this time.
In the meantime, VS 2010 and VS2012 co-exist nicely and the language specific Express editions are still available.