It's a great game but..... Despite the large number of cards available there are only a couple of strategies that are predominantly used. In particular "fast advance" and Scorched Earth. Scorched Earth in particular almost ruined the game for me.
Good game if you can get it to the table. Everyone is right, it takes a long time and you need like minded folks willing to put in the commitment for that time. The good: It is THE grand strategic 4x game. The Bad: You win by collecting points. I find this so lame. Too many mechanisms and fiddling around for what it is trying to do. You have to have the first expansion and use it's strategy cards, the game is broken if you don't.