What you are saying is totally legit. Microsoft is a company, and as engineer/web dev/creative/whatever, choosing to rely on IE for development or anything else implies you trust the Microsoft brand to help you get something out of using their toolset. We've all been burned in the past by MSFT and even if their claims about a modern browser are true, and even if it ships today with the best codebase out of any browser, there is little evidence for any of us to suddenly start trusting the spirit behind this new push.