Taking advantage of a free upgrade to Windows 10, I did just that yesterday and I immediately regretted it.
Not because it took several hours to upgrade using Microsoft Media Creation Tool, but because I did not like its look and the feel of the new OS.
The tiles bar is now part of the start menu and everything looks congested and crying out for a clean look.
I did not try out what Windows 10 really has to offer because I was already viscerally turned off by the congested and untidy layout.
(You could of course unpin all the tiles but you are still left with just the ugly start menu)
I did check out the file explorer though and found that loading the files took twice the time it did for me compared with the Windows 8.1 OS I upgraded from.
It wasn't hard for me to decide to downgrade back to Windows 8.1.
Fortunately, downgrading was a breeze and I am now back to Windows 8.1!
Here's a youtube video where someone talked about 5 reasons for not upgrading to Windows 10.
To each, his or her own as the saying goes.