New Xamarin Form project Designer load error

Hello
After many many problems trying to create a Xamarin Form project, I am finaly able to create a solution without a cascade of error message due to IOS (mostly)

But now I have another error trying to add a form and see it in designer (see message) !

So I have two question

1- Is it really a good Idea to try to use Xamarin Form or is it not mature enough to create an effective project ?
2- If Xamarin Form is suposed to be usable what are the steps to create a simple project and adding a form for pure android purpose (NOT IOS)

Thanks for any help / suggestions