Well it brings the new DirectX 12 which will be used in newer games.Also new software is made to be compatible primarily with W10 so it's more future proof.
Ragarding the performance I haven't noticed any change tbh.(Some report slight increase)
As for the cons, there might be some driver issues especially with older hardware.(I had to roll back to older drivers on X-52Pro to make the joystick work:joystick: )
And after all you have one month to return to win 7.