According to Ars Technica, Windows 10 will still send telemetry and other data to Microsoft-owned domains — no matter how tightly you crank down the privacy settings. Even with everything buttoned down, Cortana, OneDrive, and Web Search from the Start Menu disabled, the OS still phones home, using a random system ID that persists across reboots. It apparently also tries to bypass proxies to do it. "Some of the traffic looks harmless but feels like it shouldn't be happening. For example, even with no Live tiles pinned to Start (and hence no obvious need to poll for new tile data), Windows 10 seems to download new tile info from MSN's network from time to time, using unencrypted HTTP to do so. ... Other traffic looks a little more troublesome. Windows 10 will periodically send data to a Microsoft server named ssw.live.com. ... The exact nature of the information being sent isn't clear—it appears to be referencing telemetry settings—and again, it's not clear why any data is being sent at all. We disabled telemetry on our test machine using group policies.
There are some things I could do, for example, 3rd parties are coming up with "fixes" for some of the privacy issues, and you can read about those here 6 free tools that stop Windows 10 from spying on everything you do if you want to try 10 but are concerned about your "right" to privacy that you sign away with the EULA.
Be forewarned, utilities like this can screw up your installation, so use them at your own risk, as I'm not recommending any of them or taking responsibility if you have a computer that fails to boot after trying them out.
Add to those concerns, the interface is clunky and looks like a version of KDE I was running 9 years ago. Windows 8.1 runs circles around it for startup time and program execution, and even though I uninstalled all the apps, it didn't help overall performance.
I'm very disappointed with Windows 10 so far, I have nearly a year to make up my mind should I decide to try a Windows 10 upgrade, so I'll give it some time to mature and allow Microsoft to get rid of the privacy concerns and bugs that are making it run sluggish.
Based on my experience, I'd give it a generous 3 out of 10.
Anybody else here try the upgrade? If so, what do you think?