From what I've read they have given Nokia "special" access to the system to develop apps, just that entire concept that different manufacturers get different app access to their own hardware scares me. The fact that the emulator is useless scares me. The fact that it is $99 to run your own apps scares me. The fact that it was and is impossible to develop a IM-like application without having Microsoft hardcode it into the OS its self scares me. WP7 might never take off because Microsoft created an anti-developer platform. They hate developers. I'm skipping.
the $99 fee has stopped me from writing a WP7 app. And I still do not understand why a Windows Mobile like OS and the .NET framework is not available for any phone that can run Android.