I will check out those YouTube videos later.
Don't worry about the XNA drop by Microsoft: your viewers can apply most of the knowledge to the XNA alternatives. ;)And what's about MonoXNA and ANX? (It's not an ironic question: I'm working on a XNA Game and I will move to one of them in the future.)
All XNA developers will be moving to Monogame in the future.
I think they're all pretty similar in nature. I would recommend Monogame. It seems to be the most complete and has a stable release out. It also supports the most platforms if I'm not mistaken.
Should note though that to publish to the app store and play store, it costs $300 each.
Still a really interesting concept. I have plans in the future to create a game for windows using monogame. The plan is to publish on the other platforms if I make enough money from the windows version.