Xamarin
github.com
github.com
While I do like the title rule, the literal <title> tag in this case has just been generated by Github. The HN submission could be more clear.
This was before Forms came along. No clue if anyone would be interested in it, but i'm cleaning up the code to put it on github as open source.
Edit: more on topic, the open source move is fantastic! I felt the money might be worth it for not only the tooling but also the top notch documentation, but I've never been able to convince any of my bosses on this.
Apps built with Xamarin (or a similar system where you bind to platform API's) or so much better to build and use than these cross platform platforms.
Let me know if you have any other questions.
Then why would I go the Xamarin route in the first place? The whole point is to avoid having to learn both platforms. Personally, I'd rather struggle with two native codebases than to struggle learning an imperfect abstraction that still requires me to learn both platforms.
So far the C# abstraction of Android has if anything been easier to use than the official Java API, or at the very least less verbose.