I have done the update on 1 desktop and my laptop, both were running updated 8.1 from original Windows 7 loads. Both went very well and have had no issues. Over Christmas Windows 10 OEM disc went on sale so I decided to buy it in the event I ever purchased a new SSD for my laptop, as luck would have it the SSD I wanted also went on sale so I installed the new SSD in my laptop and installed the fresh Windows 10. I have to say the fresh install is much nicer than the updated version but it could also just be the SSD making things seem better.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70