I don't think desktop environment is really a part of the overall OS' style, unless you look at it from the point of view that you can be limited with Win/OSX because there are almost no real alternatives to the ones shipped.
An OS' style, to me, refers more in how it operates. Win/OSX both holds your hand and does everything for you because the makers felt that was the best way of doing it, however OSX takes that a step further with the hardware it runs on.
Linux' style is modular in design, giving the end user the "joys" of making everything uniquely their own, and that's reall the heart of the philosophy behind Linux in general. You own it, you do with it what you want.
That is not to say one is better than the other. Some people do need to be led by the hand or just want it to work without second thoughts, in which case Win/OSX are perfect for them, though Win a lot more so.