>>96846573
I'm a sucker for that 3-6m range: big enough that the pilot and cockpit makes up a measurable fraction of the torso space, but not quite so large that you're usually putting the pilot's limbs outside the frame.

I also like this as it leaves room for tanks and other conventional vehicles to still be quite potent, which they tend to not do once mecha get too big.

And in a pinch it means the bad guys can roll out a terrifying new superweapon that *is* 10m+ tall for a big scary monster that takes the entire player party to fight.