I'm planning some projects using micro-controllers so I began an investigation of the various prototyping platforms that are available. First up was Microsoft Gageteer because I already have a strong background in C# and I own the complete VS2010 Pro suite. Visual Studio Professional is not required for using Gadgeteer, Visual Studio Express works just as well. Gadgeteer module integration and controller programming appear to be very simple and straight forward to use. The underlying foundation uses the .NET Micro Framework and a subset of the rich C# language features.
The boards, mostly sold by MS partner GHI and various Gadgeteer modules form a very worthwhile development platform. The controller boards need to be more powerful than most Atmel based Arduino boards because of the special language requirements for .Net like garbage collection and event handling. These boards might not be suitable for critical real time operations as the garbage collection system may not be deterministic. The only issue for the hobbyist might be the cost of each module, cable and the controller board.
Although the platform is great for prototyping, feasibility studies or one off projects, I could see no way to easily migrate this to a smaller commercially viable product. It would be difficult to port the code to a small ARM based chip for one thing (IMHO), and it is not exactly straight forward how to breadboard this main board. I don't think this platform lends itself to miniaturization either, so if you are interested in building a small portable project, this may not be the answer.