I like the way W10 is heading and will UPGRADE my present OS.
I like W10 but would ONLY consider a clean install.
It's been fun but I will not be using W10 as my main OS in the near future.
W10 is my favourite OS.
W8.1 is my favourite.
W8 is my favourite.
W7 is my favourite.
Vista is my favourite.
XP is my favourite.
Another such as OSX or Linux.
I may bite the bullet and upgrade to 8.1. It seems MS will let you make bootable install media for 8.1 without a product key but not so for 8.0. Next time I get a real good WiFi connection I'll try to download the image.
I have many computers, and probably I won't follow the same route on all of them. In short I'll upgrade one of them, clean install another one, keep Windows 8.1 in one and keep Windows 7 in the last one because of graphics compatibility issues. I love Windows 8.1, but I usually jump to the newest technology as far as I can.