Compromise & Customize
It isn't the best at anything, but if you are willing to put in the time and make some unpalatable decisions in some places there is little you cannot make it do. If you do not like what it is currently doing you can probably change it. There are few places where there is only one way or even a way that is always best.
Good enough for the user to start
Very few things are phenomenal out of the box, but most things are usable. Unix tends to go the direction where nothing works until you configure it and Apple makes everything pretty polished, but at the cost of some configurability / flexibility.
Expect a log support tail
Windows users do not upgrade just because there is a newer version. They don't even always upgrade because of a vulnerability or bugfix. Windows users often need to be forced to upgrade, but if you force them to upgrade quickly they will seek alternative products
Users have a vast range of skill levels
Unix has a high perceived barrier to entry from a technical level from the point of view of a casual home user. Apple had a very low perceived required skill level, but does not encourage the casual user to do much in the way of customizing their OS. Windows is in between. It is only slightly harder to begin using than Apple products, yet there is a lot of simple information available, sometimes right in the install itself, on how to go about changing some pretty in-depth system configuration. This leads to a rather random skill level in the middle tier of users because if they are confident enough to try something there is a good chance they can figure out how to do it. It also leaves the more timid users without any experience in some cases because they are wary of the warnings that things my go wrong.