Well - The anniversary version of windows will remove some group policy's from Windows 10 Pro.
Source:
http://www.ghacks.net/2016/07/28/microsoft-removes-policies-windows-10-pro/ This means you cannot longer turn off things like Microsoft consumer experiences policy and much more. While I liked Windows 10, I needed (for instance) to run some older (not signed) drivers for my hardware. As this is not longer possible (only with "upgraded" systems and not with a "clean" install), I decided to roll back to Windows 8.1. Windows 10 is too intrusive for my likings, and who knows what they will cut off and cripple even more from the "Pro" version in the near future.
I certainly will not pay for a Windows version that degrades the "Pro" version into what is effectively a "Home" version. As Windows 8.1 Pro still has all the policy's in place and it is supported until January 10, 2023, I see no reason to install Windows 10 on any of my systems.
So - for the foreseeable future I stay with Windows 7/8.1 Pro on my systems (with my policy's in place, and blocked telemetry "updates"). I will see what will happen after 2023, but I have time enough to decide what to do when time comes.