There is the privacy issue things I heard that some people (outside my country) is really hate, I personally think it's just dumb to call Windows 10 is really doing that.
First, collecting data is necessary for Cortana (and Edge) for more assist you personally.
Second about email and private data that stored in server, yeah, I think every email & cloud service provider do this too, where do you think your email stored? Where do you think your synced password stored? Why they hate this if MS did this and you just trust another cloud sync service or password manager service? Is it because MS is too honest in their Privacy Policy? You think other provider can't be worst than this?
And about peer-to-peer software update, I think it can be a good thing and bad too. Good if you have more than one computers in network so you don't waste to much bandwidth for downloading update each computer, and if it set to peer-to-peer over internet the download speed will be higher. And the bad side is if it set to peer-to-peer over internet it could eat your bandwidth.
That's three topic that has been heard in here. The only thing we really hate is we can't even turn off automatic update in Home edition, internet is still an expensive thing in here. And people in here seems not really care with privacy issue things. Even if they really spying us, what for? What am I afraid to? I didn't do bad things with my computer.