I have to admit that I haven't actually tried one out, but having looked at the specs and seeing the advertisements for it, I think MS has missed what made somethign like an iPad somewhat convenient. That is, there are no moving parts or pieces to carry around or break. On paper it seems like a good idea to have a built in stand, but at the sizes they are talking about a thin piece of plastic and a tiny hinge are inevitably going to snap off/break, and then what? Add to that a keyboard (haven't we already seen how these things are falling apart at the magnetic hinge?) and the potential for something at this scale to be easily broken, and people are going to be turned off sooner than later. Where the other tablets have it right, is that there are no moving parts externally (or internally) to come unhinged, snap, break, fall apart, or otherwise create an issue.
Though I guess that is what MS has ultimately been successful at: creating a service market, and not a well functioning product.