I have to say as a Partner/Engineer/Sales person for Microsoft products that if Microsoft releases round 2 of Vista/W2K8/Exchange as poorly as round 1, everyone will abandon Microsoft for Apple/Linux. After all, look at Windows Mobile, after so many years of junk, people are moving to the iPhone. Now with Exchange support we are too, but if Microsoft kills the products again like round 1 and Apple puts out a good server, I'd move in a heart beat to their stuff (IE the iPhone) and I'd bet that have everything built in to the product like they do with CALs now.
Now don't get me wrong, I have had many good years with Microsoft products and I make a good living supporting Microsoft products, but let's face it, Vista is/was a disaster and while Exchange has been better, it's only marginally better. After all, installing a product out of the box without the ability to communicate to the outside world or being able to backup the server on the default install, that's just wrong... Microsoft took to heart the complaints of security, but in the process killed their reputation. After all, everyone I have ever talked to thinks that the Mac Vista commercials are right on when they point out all of the Downgrades to XP. Since 2007 is a fork lift from 2003 and now another fork lift to 2008, I don't think many organizations will want to go through that again and now they will be downgrading again to 2003R2 and all of the Vista/Win2008 skus will really be XP/2003R2.
Just my 2 cents, but I think the mutany will begin if SQL 2008 has just as many problems and that will be the beginning of the end of Microsoft. In the end, it won't be the AntiTrust lawsuits that destroy the giant, but bad product in the marketplace.