Experienced Windows developer use Win or Mac for iPhone?

I have been developing server side Java for many years on Windows and now want to write a game for the iPhone in my spare time. I do not have a suitable machine at home so must make a hardware purchase. Given my comfort with Windows, the fact I have almost never used a Mac and ignoring the cost of the hardware (time is money after all) should I:

A) Develop on Windows switching to Mac for final testing and deployment (as I gather you cannot build for iPhone on Windows?)

B) Just use a Mac from the outset

Not knowing all that much about Unity it still seems that using a Mac throughout would smooth the process. However, my concern is that my lack of familiarity with OS X coupled with the reality I will continue to develop on Windows during the day will hamper my efforts, such that I would do better to work predominantly on Windows.

Your thoughts would be greatly appreciated.