I like them all. Orange Star has arguebly the best Co powers (How does it feel knocking a Megatank down to half HP, only to have it complelty repaired by Andy's Hyper Upgrade?), Blue Moon has the best CO abilites(Think Olaf!), Yellow Comet easily sees though Fog of War and can blast anyone from here to kingdom come, Green Earth has the most diverse COs anyone could hope for-I mean, what other nation can become complelty invincible when they have at least 3 com towers under there command? And while Black Hole are the evil guys, they have Hawke. You couldn't ask for a more epic CO. You don't think Hawke is epic? Two words: Black Wave.