The most interesting thing about the Roller Coaster in CityVille is that it will reward you with no less than 40 Zoning Permits when you finish the last part of the upgrade (level 6). And the upgrade process itself is not that difficult: you need to collect photos in order to upgrade it, and in order to get these photos, you will need to ask your friends and get items from Amusement Park buildings that have just been released in the game.
So not only that you will receive an impressive 40 Zoning Permits from completing the Roller Coaster, but you will also have an absolutely amazing structure in your city and you’ll keep your citizens happy and entertained.