This evening, I played a quick game of Race for the Galaxy
with my son. I have come to the conclusion that the extra supplement cards add flavour to the game, but they also vastly increase the luck factor in two-player games. Viz.
I managed, through blind luck, to start the game with New Sparta, three Rebel world cards, and a production halo world. Turn one, Settle, Consume-Trade. My son, nicely, explored on turn one: I drew a six point bonus card that benefitted Rebel worlds. On my first turn trade, I scored one more Rebel world card, a six point military bennie card, and another production halo world. Turn two was lather rinse repeat.
My poor kid didn't know what hit him. 15 minutes later, he notched up a respectable score in the mid-twenties (respectable for him when playing against a strong military hand that makes the game race through). I, on the other hand, ended with a score in the mid-seventies, without a single victory point chit. My largest point total to date, indeed, the largest point total I've ever seen. My son was very brave about it. I worked hard to convince him, and my wife, that it was really all complete luck in the card draw.
I still really like Race for the Galaxy, but the luck factor makes it not tremendously much more than a quick filler at this point, and my son's interest in the game has flagged somewhat. I suspect that soon, in order to dampen the luck factor, we're going to have to play with the extra rules in the supplements and not just the extra cards and the rules from the base game.
Still enjoyable, though; highly recommended game, and great value for the money.