I agree with apalmer and worry that as soon as they get some leverage over you, you are still in trouble. I can't predict the future, but I've found past behavior to be one of the best predictors, for better or worse.
It's fine to have reservations about new technologies and companies' strategic shifts. Being a little skeptical is healthy. Objectively, you have to admit that there has been a massive sea change happening at MS over the past several years, and it's all moving if a common direction toward a more open embrace of the non-MS, open-source development community (I was as surprised as anybody when I saw that Azure supported non-Windows VMs, and I doubt they'll pull support for those).
While it's entirely possible (though I'd argue not very likely) that they could shift back to their old ways at some point, ask yourself this: Do you and the projects you work on stand to benefit from Microsoft's new direction? If so, you would be doing yourself a disservice not to try their products and services when you're ready. If they don't offer anything appealing to you, then what's there to worry about?
But the thing for me is the cash is pretty damn good and some days you can get so much done its unreal. I've worked with Unix platforms for the same time (20 years now) and know both inside out and windows is way more flexible, particularly when it comes to the end user.
What comes after exbrace, extend is no longer extinguish though. Any sane person these days makes portability choices. We're rebuilding our stuff as microservices now (4MLoC C# projects won't survive without this). Now their stack is getting a look in because we're already experienced with it but if they shaft everyone this time, its trivial to port our services away to other tech. We rewrite most of our stuff perpetually so they'll evolve into zero risk.
It would be interesting to poll HN to find out who got actually burned by EEE and how.
I'll believe Microsoft has turned a new leaf once they've open sourced their Operating System's Kernel and their Browser Engine and stopped development on DirectX or handed it over to Khronos or ISO/IEC and/or open source it.