The learning investment is what makes me most hesitant to use Xamarin. It was supposed to be less of a learning investment because we all have C#/.NET experience, but now I'm not so sure. It now seems like we're going to have to dive deep into learning iOS and Android specific UI concepts anyway, and on top of that learn Xamarin concepts and quirks, and if we want to continue using Visual Studio when the trial is up we'll have to pay $1000/year. Maybe we're just not the target market.
This includes hundreds of samples: http://developer.xamarin.com/samples-all/
And lots of detailed guides: http://developer.xamarin.com/guides/
And dozens of videos too: http://developer.xamarin.com/videos/
As for Xamarin University, the vast majority of that experience is live, interactive learning with a teacher. That's why it costs money. The recorded versions of those interactive classes aren't that useful on their own. But, we're working on developing some good standalone e-learning content and when we do it will be widely available.
It is 1:1