I think, you should try out W10 and see for yourself. Personally, I can't stand poor memory/pagefile management of Windows 7 SP1 anymore (still running one box for testing purposes), compared with the latest build of 10 x64.
The only practical downside of W10, is automatic updates/upgrades*. I've seen instances of installing wrong drivers*2, for example.
* During upgrades you may lose Windows settings/tweaks and software that Windows considers unsafe. You can postpone that in the Pro/Enterprise version though. Still, could be a time bomb of some sort. You can disable updates via a registry tweak and use a third-party updating system instead, which is a hassle though.
*2 WU offered me to install Geforce 8600GT drivers for my Intel-enabled desktop. Still scratching my butt as to how that did happen, lmao (I never actually had that card installed in this system).
But speaking of pure performance, W10 x64 easily 0wnz anything Microsoft has engineered before.