Awesome. Just put some old second-hand mac mini or macbook in a closet, and it should work. Now all we need is some sort of tool that converts XAML to whatever the layout systems in Android and iOS are called.
$999 a year is insanely high though. I could see them attracting individual developers with something along the lines of $400/$500 once, but as pricing stands now they're just going to attract businesses. Which, obviously, makes sense, but still. They should work out some sort of Bizspark partnership.