Is Leopard the end of Windows Vista? Is this it for Microsoft's latest Windows client? Will Vista bow to the cat from Cupertino designed to replace Mac OS X 10.4 Tiger? The answers are of course nothing but a matter of perspective, and in this context, Microsoft and Apple are bound to have disjunct views. The Cupertino-based hardware company has set Leopard free on October 26, and is now already applauding the cat's sprint.

And the truth is that Leopard's debut is nothing short of impressive with two million copies of the operating system sold in just the first weekend since the platform hit the shelves. Apple's Chief Executive Officer, Steve Jobs, went on a limb and interpreted the strong initial sales of Leopard as a future guaranteed hit. Moreover, Jobs, even took a swing at Microsoft claiming that Leopard is converting PC users to the Mac, and as such abandoning Windows.

Microsoft failed to reveal the numbers Vista accounted for in its initial days on the market starting at the end of January, but following the operating system's first month on the market, the company boasted shipping in excess of 20 million worldwide. Vista went on to double the volume of shipped licenses worldwide after four months since the launch, going to 40 million in May. Six months after the release of the operating system, Vista passed the 60 million milestone. And this month, Microsoft revealed that as Vista is closing in on its ninth month of general availability there are over 88 million licenses shipped at a global level.

According to data made available by Net Applications, Vista accounts for 7.38% of the operating system market while the combined shares of both Intel Mac and Mac OS is 6.61%. Apple is bound to increase its grip on the market following the availability of Leopard, but it remains to be seen if Mac OS X 10.5 will keep its launch momentum or if the initial sales will tone down.