Tigris and Euphrates is a very strategic game that maintains a nice balance of optimizing your own position with a "screw your buddy" mentality. Especially fun is laying down a tile that combines two kingdoms and causes two of your opponents to duke it out. Of course, the winner of the conflict will score several points, so this should not be done casually.
The pieces themselves are high quality and the game is visually pleasing. The only complaint I have along these lines is that the monuments are a little difficult to put together.
Throughout the night we first played this, everyone kept saying how it wasn't better than Settlers of Catan. Personally, I think the game is superior as a a pure strategy game, but is arguably less interactive than settlers. Game time is roughly 2 hours.
My Score: 8/10