The ability to adjust the size of the galaxy (creating outer space expanses that would take months to complete, if so desired), the frequency of habitable planets, the evolutionary curve of the species and a host of other aspects make this a comprehensive tool for the serious sci-fi RTS gamer.
Unfortunately, it's rather lacking in terms of multiplayer, which is somewhat unforgivable these days considering the size of the game, otherwise Endless Universe could likely take on Eve Online in terms of scope. So close, but ultimately a few parsecs short of a light year.
