

In that case such app could sell less than a "normal" Java app that looks and feels like all other Java apps. On the other hand, you can use Mono for Android to develop apps in C# in VS, but they won't look as smooth as the native apps (some functionality might be missing, look-and-feel slightly different, etc.).

Thus, if you use it out-of-the-box, you will lose all Java-specific Eclipse functionality (IntelliSense for Java, Java debugger, wizards, etc) as well as numerous Android plugins (that are Eclipse-specific and won't work with VS). You want to keep on making normal Java-based Android application, but use Visual Studio for development? Then it's bad news, as Visual Studio has no built-in java support. That depends on what you actually want to achieve.
