More routes to victory, more starting worlds and yet another set of player cards. With the Gathering Storm you can now play 6 players as my playgroup does more often than any other game. This is a must-buy along with the base game and TGS.
This expansion is also worth getting (buy both). It fits in the box with the main game. While I don't find the military takeovers to be that consequential, the addtional cards, and especially the goals are worth every penny if you love R4tG. Which honestly you should, because it is awesome.