It's one of the few Total War games where the historical battles are better than the campaign, for sole virtue of you will be banging your head on your desk over and over again in frustration over losing yet another battle. The vast majority of historical battles in MTW/RTW/M2TW were easy, but Alexander will put you in your place. You need to be exact, precise, and lucky to win the historical battles.

However, the campaign itself is good. Unfortunately it's FAR too short. If Alexander dies (in any form, such as old age), the game is over. You need to be quick and fast, just like the real Alexander, if you want to conquer the world.

If you (like me) really love Total War and want to try all aspects of it (or just want the computer to kick your butt in the historical battles), buy Alexander. If not, I'd hold off on buying it, as it's just Rome in a pretty skin with far fewer factions to conquer.

I guarantee you will forever hate river battles once you play the expansion, and will cringe the next time you will have to cross one in Vanilla/BI.