Halo Wars developer blog, lead technical designer Tim Deen discusses the game's unit balance. Most Halo Wars fans are probably familiar with the game's "Rock, Paper, Scissors" (or RPS) balance, but Deen goes into extreme detail, even providing the complex chart seen above. If you'd like to move beyond RPS basics and start learning the difference between a 'soft' kill and a 'hard' kill -- and which units do which -- it's definitely a good read.
Sadly, Covenant fans out there are left in the cold, as the chart itself only addresses UNSC units. Hopefully, someone at Robot will be kind enough to put together a new chart for our Covie friends. Then again, we only build Brutes anyway.