Back to the original topic: coincidentally I decided to finally bite the bullet and upgrade my home laptop last weekend. I've had Win 10 on my work machine for a month and like it very much. I prepared my cheat sheet (options to select to reduce phoning home behaviour), and pressed the 'upgrade now' button. Waited for the heavens to fall........
Home upgrade started, rebooted, went nowhere......after googling 'Windows 10 upgrade hangs' on my phone, I rebooted the laptop and Windows 7 reappeared - phew! It turns out certain Samsung laptops have a wifi adapter which is disliked by Widows 10. So at some point, I will open up the machine, remove the offending device and retry the upgrade.
Post roll-back, all my files were still intact, so I haven't needed to use the precautionary backup which I took before upgrading.
On a related topic, I'm pleased to see that if I wait a couple of years, I'll be able to indulge my enjoyment of SQL Server while no longer being tied to Windows. Linux - way to go! Does Linux spy on its users?