I note that you didn't provide an example.
He did--he called out Rdio (http://rdio.com) as an example.
Presumably that is the only one. Xamarin features it, but everything else they feature is an in-house corporate line of business app. If there are 'lots of great apps' out there, you'd think they'd tell us.
Not encouraging.
Well, right now I have just built two "in-house corporate line of business apps" and so far, the pay was reasonable and time-savings due to underlying framework huge :)
That's fine - the point is that in those cases the end-user is not the customer, so cost-savings trump user-experience.
There are some case studies here: http://xamarin.com/customers
There are lots of great apps out there, Rdio was one of the more prominent early ones and it is also interesting to note that Unity3D games run on the same underlying framework (mono) http://unity3d.com/showcase/gallery