AI War: Fleet Command has incredible AI and the largest number of units (30,000+ in most games) of any game we know of. It's entirely cooperative-focused, with 1-8 human players competing against 2 deadly AI players. Campaigns take place across a galaxy of 80-120 planets, lasting around a dozen hours across multiple play sessions. RTS is never more fun than when carrying out joint maneuvers with your friends.
Version 1.009 features: several new ship classes, new display modes and control options, even better AI, dozens and dozens of player-requested enhancements.