I got this game recently, and its very cool, definately a change of pace from settlers. I've played that game so much that I never want to play it anymore, and the cards are all covered with pizza grease and stuff. Starfarers does a good job of building a new game around the basic core mechanic from settlers, ie roll 2d6 for resource production, and then trade.
I have to say though, that I consider settlers a classic game. Not as much as Chess or Go, but probably above Monopoly. This is because the game is very simple and elegant, and the whole thing revolves around the core game mechanic. I've never seen any be boardgame be so well recieved by so many people. Starfarers doesn't have this same classic fee, because of all the encounter cards and wierd stuff.
I also got the chance to play Tigris and Euphratis recently. It seemed confusing the first time, but I think its game design is also very elegant. And the strategies involved seem really complex and interesting.