My experience was terrible. First attempt to upgrade went all the way they the process but left me with 8.1. Second attempt got me to a desktop that crashed and left me at the auto fix screens. Nothing worked. Had to go through restore. Third attempt got me to a working desktop that uses lousy default graphics drivers and no audio
Not impressed.
I have several Windows 7 Professional machines that I am going to upgrade eventually, but I think I will let a few million other users finish beta testing it first. I have a few XP machines left that I would love to try Windows 10 out on, but MS is not supporting upgrades from XP.
I have used every version of Windows since 3.1. Windows NT, 2000, XP and 7 were all definite improvements. Windows 95, 98 and 8, not so much (though 8.1 was a big improvement over 8). Vista was an abject failure.