I've had opportunity to play with it (at work), but given the price, not a likely choice for my hobby projects. It's not without its drawbacks, either. Since it's not native development (for Android), we 'e adding more moving parts into the equation.
And, for instance, most of the sample apps for Xamarin.Forms wouldn't even build when I tested Xamarin.
I had to fix folder paths (to Android SDK) manually.
The product is superb, but Android is under rapid development and Xamarin folks will always have to play catch up with them.
And in meantime, weird things - all sorts of incompatibilities - are bound to be popping out.