I don't know who is the winner.
First, if we say that Apple will win, it is not true. Apple is wonderful in past. At that time, microsoft is just a tiny company. IBM can't defeat Apple. But what is the situation of Apple today? It is marcket share is smaller and smaller. Even though, it seems that Apple begins to gain its marcket share, Adobe has said that more and more design people move to Windows. I think this is true.
Second, although Apple choose OS X, the UNIX kernel as the core of its next generation operating system, it only take people from UNIX, but Windows. Of course some users move from Windows, like me, but more users move to Windows.
Third, Apple has tried to gain its marcket share from Windows. But its resource, Engineers and financial is not so strong as MS.
Fourth, Decision is the key role. Apple makes a lot of mistakes. These mistakes weaker down Apple. OSX has been developed for more than 10 years, and what is it now? Slow and Incompatible. I don't know when its speed is up although a lot of people say that the coming version runs faster than ever. MS only spend 3 years and developed a great product. Even though a lot of people say that OS X is better than XP, but the fact is that, more people choose XP. Saying is not Doing.
Both Apple and MS do it what they want. More on themselves and on custumers. MS give more "CONVENIENT" than we can bear, but Apple try to make it less "CONVENIENT" than we can bear. Let's look at PowerMac Silver, what is missing? No CDROM/DVDROM eject button!!! Apple trys to make it beautifull, but ignore the users' feeling. MS make a lot of AUTOMATICs. We can full customise the destop.
I don't know who is the winner. Commercially, maybe MS, because it develop it is product faster and easy to use. For favorites, I choose Apple. But not all users like me try what he love. But more reason is software support and convenient. Commercial users will choose MS for faster production and faster and wider support.