(Sorry for the late reply). In particular I was hoping that I would be able to use my Exchange account in Mail without needing to be connected to a VPN. Exchange mail works perfectly in iOS without the need to be connected to a VPN, although I haven't discovered a way to do that with OS X yet. I'm assuming ActiveSync is what makes it possible for iOS.
I have the same question. For those of us that work for companies that haven't updated exchange since 2003, we can only use activesync and get our mail on iOS devices and can't on the mac computer. So now I am wondering with all of this Cloud stuff going on, what is going to happen between my mail app on my computer and my iOS mail? Mail on the computer didn't support activesync and this has been a huge problem for many of us.