
I don't know about the dogfood thingy...but anytime the "user community" has to switch CM tools there is always apprehension, to say the least. I've worked many contracts as a Lockheed Martin employeee and in the private sector and this is always the case.
It's not a Microsoft thing. Changing CM tools means you change how you perform CM. Some tools do not have the same basic features as others, for example, so there is not only the "culture" change that people are apprehensive about, there is also the way things are done. Developers have to change how they do things. Testers have to change how they do things if their testing suite of tools are integrated with the CM tool.
People should be very cautious changing their CM tools. A lot may be riding on the success of the tool you are changing to.