What I am about to say here is only
my opinion. However, I have to give you word of warning. I have been playing whole MOO series and a dozen other similar games and Space Empires IV of course. single play in SEIV sucks badly. The AI is not that good (it can fight you only with bonuses), computer opponents seem sterile and you get to war with all of them sooner or later (propably sooner).
However, the reason I hang here and like this game is that it's multiplayer abilities are beyond comparison. There is dozens after dozens mods for the game, which are not even hard to make and no two games are EVER similar. I am talking about SEIV PBW (Space Empires IV, Play by web) where is all the time dozens of games going and you can choose one or several to join in and start playing against humans. If you like multiplaying, SEIV is definately your "best buy".
However, welcome to the forums and form your own opinion of the game
SEIV Play by Web