Actually The Mongols Ruled Their huge empire for a very long time and ruled the lands well, Alexander dies before even returning to really govern his mighty empire.

Ghengis also set up the first "pony express" running from china to his persian gulf holdings maikng rule of his vast empire that much more simple

Alexander...

Ghengis just invaded and killed people



ALexander invaded and killed people, but suceeded in governing his conquered territories much better than the mongols

Ghengis Khan
His Empire was Larger than Alexander The Greats and his empire lasted over a Hundred Years After his death.
Military wise the Great Khan was able to use a small force (in comparision) of mostly cavalry to conquer some of the most advanced and powerful nations of the world including China he also experimented with biological warfare using catapulting plague ridden bodys in to cities he was sieging.
Tactics wise the Khan was a genius pioneering what in modern tactical doctrine is called "manuver warfare" and is what the Marines are adopting as their main strategy.

Catherine the Great and Alexander the Great.

I haven't studied much on Khan.