The big feature in Apple's new product is Exchange support built into to native OSX applications. Microsoft has provided support to OSX through Entourage, but that has fallen short to the kinds of features Mac users desired.
What this shows is that Exchange continues to be the professional email platform of choice no matter the operating system Apple has long realized that their OS needs to support Exchange to have chance of gaining market share in the business market.
The Snow Leopard release just gives credence to that claim that Exchange is and will continue to be the service of choice for business email.

