With how buggy their flagship OS has become, why would I trust anything else they release to be better? Or even if it does work well now, why should I expect it to stay that way? Microsoft has burned through all possible goodwill at this point, at least for me.
UI of Windows is buggy and inconsistent. Kernel and low level stuff are actually very stable and good.
Microsoft doesn't have a very good track record with security or privacy. Maybe it works, but yeah you'll probably get screwed over at some point.
Still, the fact that it's open source is a good thing. People can now take that code and make something better (ripping out the AI for example) or just use bits and pieces for their own totally unrelated projects. I can't see that as anything but a win. I have no problem giving shitty companies credit where its due and they've done a good thing here.
This isn't supposed to replace Windows, and it isn't a GUI desktop operating system at all. I doubt anyone working on this has anything to do with the modern Windows desktop UX.