I'm the odd man out here. I still have Windows 7 and love it! My PC crashed a couple of years ago. I had the original (W 7) install discs but needed to go online to update some of the things and that was not an option. My DH works for a school. They gave me an old PC and installed W 7 on it for me. I was (and still am) in heaven!
I do use the cloud - One Drive/Skydrive - to store some of my files that I want access to while traveling. When traveling I use a Windows 10 laptop.
On my W 7 PC I use Firefox. Because the laptop I use when traveling is actually another 'school' laptop that was a (long ago) loaner to DH I have not downloaded Firefox on it. We were on vacation this past week and I was using the laptop and Internet Explorer (or whatever the W 10 version of that is called). And let me tell you, without the ad blocker that works so well in Firefox it was painful!
And this will make most of you gasp - but I have no additional security on my PC beyond what my ISP provides. I have always been of the belief that hackers do not care about my PC. They get all they want from hacking into major companies - banks; department stores and the like. They get the same, if not more, of our personal data there. They can't be bothered hacking individual's computers. I've never had a virus issue. I've never been hacked.
So...as I say...I'm odd man out. If you have the option/ability to go back to W 7 and you want to - go for it. If you are highly security conscious - you may not be able to. Outside vendors' security software can still be updated but W 7's internal security and any OS 'glitches' will not be able to be updated.