I’ve used AE on both platforms, and the user experience was identical to me, except for the cmd/ctrl key thing.
AE is very processor-dependent. On a faster machine, AE runs faster.
Drive speed is relevant when accessing frames, but as the composition gets more complex, drive speed’s role in the speed equation is reduced.
OpenGL performance is irrelevant. It’s not good on both platforms, so most people switch it off.
Nit-picking system configs for speed gains is just that to me: nit-picking.
AE is not the reason to pick one platform over another. If you want a specific 3D app or video editing app or you’re really used to one operating system, then those are good reasons to pick one platform over another.
Personally, I now use macs because for me, I’m faster using them outside of AE.
Inside AE, it’s all the same to me.
That’s just my opinion — you may be faster on Windows outside of AE, and that’s cool.