I'm surprised nobody rated the Cossack higher. It has a real uniqueness being the earliest blitz unit (other than Armies) by a longshot. It is useful really until the end of the game with its movement and can defeat redlined Infantry regularly. The blitz makes it like having extra units around and you get Elites and thus MGLs like crazy. If an enemy SOD invades, you are almost guaranteed an MGL or two every turn if you've got some artillery. Personally this is in my top tier. The Hwach'a I would also rate higher since it is truly unique and since I use artillery so much anyway. I haven't had much luck with the Berserk. Everyone else seems to like it, but it's expensive and really requires escort units since it's slow and has mediocre defense. Another couple I'd rate lower would be the Keshik and Bowman. Other than that I pretty much agree with all the rest!