Couple caveats to people thinking about buying this game (I bought the game and will enjoy it).
It is always online, there is no single player game. You can go private and not play with others, but the game itself has parts that are processed on Maxis servers.
The launch is kinda a disaster. 30 minute queues to start playing a game this morning. Game breaking bugs are occurring for some people which is requiring people to use the rollback feature that was included in the game.
Cities are small. So they went with the region map but the actual cities themselves are quite small.