> You can simply choose not to use Cortana or to disable it entirely. Google Now & Siri support the same functionality but ironically don't give you the settings to disable it, so nobody bats an eyelid.

Siri can be disabled. Location tracking to improve contextual understanding can be disabled separately if you don't want to disable Siri completely. If you disable Siri, all data is deleted. You're also informed of exactly what data is uploaded.

> Beyond that you only really have so called "basic telemetry." Which tells them when you launch a Windows 10 "app" and some basic computer information. But even without that setting/ability the apps themselves could conduct the same reporting (via direct HTTP requests), the only reason it is even a setting is because Microsoft unified it to make developers lives easier and to better aggregate the information their side.

Does Microsoft let you disable this? Apple offers you a prompt like this one http://imgur.com/aBzTNsV on every major (x.y) update, and shows you what data is being uploaded (as well as letting you disable it) in settings.