Windows 10 works now. (except for those that find it does not work for them)
Many have chosen to use it as their primary.
I have found it fully functional and a nice system to use.
See, the devil is in the detail. I need High Contrast Themes because I have only 40% vision and cannot decipher anything on a white page. But In W10 this has not yet been fully implemented. The whole Settings area and some other areas do not work in high contrast. I assume they eventually fix that, but for now I can only make very limited use of W10.