My new Acer laptop came with Win 8.1, with the option to upgrade to 10, which I did straightaway because I'd heard so many bad reports about it. A pop up appeared on my two year old desktop so I tried to download Windows 10 on there, but it tells me my processor isn't compatible so it's still on Win 7
Having both I prefer 7. I find Win 10 difficult to operate, I might have got used to it if both were on it I suppose.