You want to trust Microsoft to keep their words? Really? When has that ever happened in the past, ever.
You can trust them to do everything in their power to screw you over and nothing short.
This isn't a fanboy hate post either. From a purely business perspective aligning with Microsoft is toxic.
You can trust the legal system though ... what you're looking for it's called "estoppel": http://en.wikipedia.org/wiki/Estoppel
I am not a risk taker and will follow after you succeed.
I know its fashionable to hate Microsoft, but sometimes it creates a narrow-mindedness which results in, we Entrepreneurs or Hackers to miss out on good opportunities if we are going to be this religious.
This isn't a fanboy hate post either. From a purely business perspective aligning with Microsoft is toxic.
I don't know what you mean by toxic, there are 1000's of companies like Adobe, Autodesk, id Softwares, EA etc which went on to make Millions and Billions of Dollars because they aligned with Microsoft and built over their platform. If maybe John Carmack was religious enough to hate Microsoft or not build over their platform, he wouldn't have created one of the best game developing company. Maybe he would have spent his time discussing what color the next version of Macbook would be, on discussions.apple.com.
"For the last word I'll hand over to John Carmack, Technical Director of ID Software, who used NeXTSTEP to develop Doom and parts of Quake (that's right!): "We developed lots of products under dos (mostly borland c++), and never want to again. We went through five major iterations of our tools under DOS, and they are all junk below our first iteration of NS tools. You can't really just point at specific things and claim superiority. It is the complete package that has the appeal. NS is the best tool I have found for MY development work."
from http://www.paullynch.org/NeXTSTEP/NeXTSTEP.TechReview.html