I have had it since day one of it coming out, and I have only played 2 games of a map from the map pack. It's not worth it. I know a way Robot could make people have more of a chance of playing them without splitting the community, but their is no use of mentioning for like the 100th time.
I got Halo Wars the day it came out. I have flaming warthog and honor guard wraith. I even have the general rank and all the achievements. No one can beat that.