I don't like the halo games, but I did buy this one because of the God complex and the Age of Empires type feeling. Didn't stop until I beat it. It was quite fun.
I only just got it but from what i have played it is a very good game. The best bit about halo wars is probaly building up big armies to destroy your oposition Cons: -
very cool strategy game with some interesting challenges. difficult enough to be interesting but even on Heroic, it's not so hard as to be discouraging.