Well, the best (but not my favourite) unit in Alexander is definitely the Phalangitai, who are almost unbeatable. While they are quite expensive, they are the best infantry in the game and can be recruited quite early in the game.
However, I was surprised to see that the Companions were available as mercs...
Invincibility lies in defence, while the possibility of victory in the attack -Sun Tzu
Akouson me, pataxon de (hit me, but first listen to me)-Themistocles to Euribiadis prior to the battle of Salamis.
[This message has been edited by Alex_the_bold (edited 04-29-2012 @ 01:25 PM).]