The strengths of Apple software applications lie in their consistant interfaces, their ease of use(largely because of this consistancy) and the way they integrate very well with other applications, and the OS. Safari for Windows does none of these.
Being a 50% Mac user (Mac exclusivly at home, PC's at work) I fully appreciate that apple has very good guidelines for interfaces on OSX applications. Its because of these, and because of the boundries application developers can push to make their products more user friendly (delicious library). Windows however, also has simiar guidelines, though not as well inforced.
It's these guidelines which allow us to resize our windows from things other than just the bottom right corner of the screen. They mean our title bars have the titles in the top left of the screen, not underneath my minimised Winamp where I cant read it. It means that on the whole CTRL+TAB will cycle through the tabs you have open. It means text can be rendered consistantly, using your OS's text anti-aliasing settings.
Consistancy within your products is good, but consistancy across the platform you are using is a better sort of consistancy. Its the same reason as even though I'm a devoted Opera user at work, I'll use Safari on my Mac because of its more consistant interface.
I know a lot of windows based web developers have been crying out for Safari for Windows for a long time. Assuming the same rendering engine is used, this is a great day for the web. Now more pages will work in Safari because people have the ability to test in it.
Except they wont.
People don't even test across the current windows browsers effectively. Until I'm proven otherwise, I'm going to consider that argument pretty much invalid. But that's not the point of my rant today.
It seems obvious to me that Safari for windows is not meant as an end user product, but merely a testing platform to get windows developers on board for developing 3rd party web apps for the iPhone. Just as the windows version of iTunes is merely a platform to get people using iPods on their PC's.