I haven't looked at it in depth so I don't know how it compares to the offerings listed above. My guess is that it's closer to AppEngine - you write to the MS stack and deploy on their infrastructure, the details of that infrastructure are opaque to you.
That sounds about right. I write all my stuff on the Microsoft stack whenever I have a choice, and still I'm not at all excited about their Cloud offering. They really missed a great opportunity to dominate the space.
I haven't looked at it in depth so I don't know how it compares to the offerings listed above. My guess is that it's closer to AppEngine - you write to the MS stack and deploy on their infrastructure, the details of that infrastructure are opaque to you.