For 400USD looks like Monodroid is definitely an expensive way for .NET developers to join the Android game. Using Eclipse and the Android Development Toolkit(ADT) an experienced .NET developer will be productive in no time. I downloaded the tools 1st thing in the morning and by midday I had a simple data driven application with the appropriate test coverage.
The Eclipse tool support for Android is unbeatable. You get design surfaces, inbuilt editors for resource files and the comfort that these tools are mature and bug free. The other side effect is that you end up learning Java.
Viva free tools!