Mix is going really well. We have a much more diverse public here than at the usual Microsoft dev conferences. I've never seen that many Mac laptops at an MS conf. We're getting absolutely great feedback from attendees. Here's a sample from a conversation: "If you had told me two years ago that I would be at a Microsoft conference one day I would have just laughed at you, but this is great, it seems like you guys actually like us."
Plus, we have some documentation. About time, I know ;) .
Oh, and one more thing: you can build a site with Atlas today and go live with it. This doesn't mean that we're freezing the object model. We *are* going to continue developing the platform further and stuff is going to change, but we wanted to give our early adopters the green light to publish their stuff publicly on the web.