I’ve been on the Windows 10 Insider Preview program since last December. I’ve had various builds, but on the 18th of this monnth overnight it installed the final Windows 10 and would no longer accept new entrants to the Insider Preview opportunity. So I have Win1`0 free. Forever.
Not forever. I guess you didn’t hear.
I also have the Ubuntu 15 upgrade from U14 on another desktop. It takes getting used to, but accepted all my hardware without a hitch on installation. Win10 was not quite that easy to install. But both are OK. I do think that in the end, Linux will be better.