A really amazing engine building game. The rules are simple but it will take the average non-gamer at least a single game for all of it to sink in, but once it does it really is amazing. Also the amount of tokens(all of which are of a very high quality!) you get is amazing.
The game also comes with 2 expansions, and it recommends using only one at a time. If you don't mind a bit slower game, using both expansions works just fine, its the only way I've played, and probably the only way I will.
Plays very similar to imperial settlers, but improved and simplified greatly in my opinion. Some people may prefer imperial settlers due to the theme and the various unique factions(the factions in 51st state only have slight differences).