For security, I prefer Windows 10. Windows 7 had a fatal security flaw in it that hackers could use to completely lock you out of your system entirely called a System Key, or SYSKEY for short. This was a function that was removed in later windows versions.
I'm not a big expert, but I have to say I really don't care. However, though, I find updates annoying because my 3D computer art software often loses the ability to work and there's no free upgrades. Who has had a similar problem? Anyway, I don't pay much attention to what system my computer uses generally. Well, everything updates automatically - so I am more concerned with forum software or theme updates.