No, I haven't looked at Xamarin yet. I've played around with Android development a little but haven't gotten around to setting up all my dev tools on my new laptop yet.
I was going to try Adobe PhoneGap or Apache Cordova after getting Android Studio and the NDK tools installed.
I've already installed Microsoft Visual Studio but haven't installed the Xamarin extensions yet. I might take a look once I get a bit more comfortable with C#.
I'm an old school C and asm embedded system programmer at heart since I come from an electronic background.