I upgraded three systems and have not had a single issue. This includes my system I set aside strictly for photography where I do all my processing using CC. All has been working fine. Mind you, I don't find anything impressive in Win10 so I see no reason to upgrade other than Microsoft will eventually phase out all older operating systems.

Win10 is actually a step backward to Win7 to accommodate those who didn't appreciate the "Start" page over the "Start" menu. Other than that it is simply just another operating system and nothing to get excited about other than the fact it will mess up some users as most new operating systems do.

Oh, by the way - you do want to go into the settings and shut of all the Microsoft privacy and advertisement nonsense they have added.