I have the first one, and though I'm not a big RTS fan, I am a Halo fan and since it's canon I wanted to play through it. I'll eventually get this but I'll wait for a price drop.
I'm surprised RTS isn't making a come back with the advances made in voice activated computer technology. Full voice commands would make RTS much more accessible to mainstream gamers.
Halo Wars was one of my favs, so I picked this up. Really fun so far. Leader abilities have changed a bit, so re-learning strategies and such. I'm a sucker for strategy games like this.