The main votewinner for me with Win10 is the return of the Start menu. Gosh, the 8/8.1 abomination was a checklist of bad design.

As long as you turn off all the tracking of everything you do with your computer as well as the annoying Cortana, it's a superior upgrade. The only quirk I've noticed so far is that connecting to VPNs involves selecting your VPN from the notification panel, clicking it, and then being directed to a dialog window which...asks you to choose again.