I upgraded to 10 because I wanted to play with the 3D printing tools otherwise I would have stuck with 7.
The spying was a worry, at first I used O&O ShutUp10 which does a good job of protecting privacy, but the settings kept reverting back on each upgrade.
I then found the best add on for win10 was a Raspberry Pi , running PInhole, and using wally3k lists.
It is amazing at how much traffic windows 10 generates on the network, it is constantly phoning home, fortunately all now blocked.
And the big advantage of pihole - stuff, my daughter who has development delays is safe online and gets no add to click by mistake on her iPad, and my wife is now able to use the web advert free which is all the better for our bank account, and all windows 10 talemetry is blocked,