I finally had the opportunity to play Settlers of the Stone Age this past weekend. As a fan of Klaus Teuber's Settlers of Catan series, I was looking forward to playing this game.
The basic mechanism is the same as in Settlers of Catan, players build settlements which allow them to collect resources. Instead of being set on a fictional island, it takes place on a map of the Earth. The goal is to earn 10 victory points, which are earned by building settlements and performing other actions on the board. In Settlers of Catan, players build roads out from their initial settlements and must build their future settlements only on places to which they have built roads. Settlers of the Stone Age does not do this, but borrows from Starfarers of Catan. Players have nomads that walk along the board and, after paying the appropriate resource cost, can be converted into settlements.
Players initial settlements are placed in Africa. From there, nomads wander outwards from there to Europe and Asia. There are development tracks that players need to advance on: hunting, clothing, building, and food gathering. To expand across the world, you need to improve your skills. For example, to move from Asia to North America requires level 3 clothing and level 1 building. During the game, player actions cause Africa to turn into a desert, causing settlements there to no longer produce resources. This provides a clever way to force people to expand to the rest of the world.
Settlers of the Stone Age has only 4 resources that are produced (rather than 5 for Settlers of Catan), and the resources seemed much more balanced. As was overheard in a conversation about Settlers of Catan "There's only so many things you can do with sheep".
Both games I played were very close (10, 9, 8, 8) and (10, 9, 9). My only complaint about the game is that it felt like it took a long time, over 2 hours a game, though this could have been a result of inexperience with the game.