This is really not good enough...
.... MS need to sort this out PDQ. The sign in process in Win 8 already is a bit weird with ODFB and Office, and the confusing prompts for a Microsoft Account (aka my hotmail log in which is what it will be for a large number of people I suspect).
It doesn't seem that hard to design a sensible single sign on for Win 10, but that woudl require their product team, heaven forbid, from working together for once