I upgraded from 7 to 10 FOC July/August 2015, it took four attempts, generally failing within the last 90%, once installed I started to get a hard drive failure imminent, my touch pad would no longer function the same, a borescope camera would no longer function, I attempted to stick to all Microsoft by using Edge, basically at the time I wished I hadn't moved, but recognising it is supposed to be the way forward I persevered, I went so far as to purchase a new laptop with 10 installed, in all I'm not thrilled with it by any means.
I have lost count how many times Internet Explorer hits a problem and stops working then has to close down, so nearly a year on from everything functioning correctly I now encounter problems that did not exist prior to the upgrade.
Well done if you succeeded free of any hiccups, this tends to be the norm for large companies who will claim an exceptionally high success rate if 95% of customers are happy, that's fine unless your in the 5% that are not, 5% of how many million customers is a lot.
AND yes I replaced the HD in my old laptop and that fairs just the same as the new one.