While Windows 10 is a solid operating system, it is nowhere close to being perfect. Actually, for 2015, I am comfortable saying Ubuntu was the superior operating system. The Linux-based OS is rock solid, while being straightforward -- no confusing privacy settings, silly live tiles, or aggressive upgrade tactics. Quite frankly, Ubuntu 15.10 with Unity is currently my favorite operating system. This is saying a lot, as I have historically preferred Fedora with GNOME.
Ubuntu Linux 16.04 'Xenial Xerus' Alpha 1 available now