If you like the base game then this adds you more options.
There are generally 2 types of expansion, those that add new mechanics to the base game and those that add more of the same.
This expansion fits firmly in the later catagory but for a game of this type that is certainly no bad thing.
This adds more citizens, monsters, dukes and domains to give you even great variety to your games. If you find yourself already playing this game a lot then this is certainly an expansion for you.