My wife bought me this for Christmas last year and we've played it quite a few times.
We both really like it but you need a good amount of time to have a full game - it's a whole evening activity and can take a few hours to play through.
It's very tactical and the scope and replayability (is that a word?) factor is great. My only criticism is that you can get ahead by trying to anticipate which cards might come up (e.g. Europe scoring in the first phase) and gain a significant advantage.
The fact that there are multiple different ways to win/score winning points is good - e.g. armies/realignment/space race.
Overall a fantastic game, one that we don't play as often as we should.