I remember the 4 countries from Warbirds - Red, Green, Gold, and Purple. It was kindof fun to have more countries (supposedly they all had unique personalities), but what happens is the two neighboring countries gang up on the smallest country. I think HTC went with 3 countries to try to eliminate the imbalance problems with 4.
For a game called Aces High though, I've always thought 4 countries - Spades, Hearts, Diamonds, and Clubs would be more appropriate than Chess pieces...