The core problem with windows 10 for me is and remains the crappy driver situation. Drivers on windows are far less robust than on OS X, and OS and/or driver updates create many more problems. This isn't tied to any particular windows version, but W10 suffers from it more because updates happen with much less control over the when and where, which means drivers break in more awkward moments.
An example from my own workplace is that a lot of my coworkers have had their laptop keyboard break after a W7 update. Windows reboots to update, and ctrl-alt-del no longer works, not on the built-in keyboard and not on an external one, so you're locked out. The solution is connecting via remote desktop and logging in once, after which windows update picks back up and fixes the problem, but that's not always a convenient thing to do. I bet that microsoft doesn't even see that in their metrics, because to them it's just a remote desktop login, so they probably think those updates don't have any problems (after all, the update gets installed and people seem to go back about their business).