It is a self guided tour and all you need is 5 minute. When we went there, there was no activity in the factory whatsoever so all we saw was the history of chocolate and the company on the wall. You will get a small piece of pecan brittle and a piece of your choice: white, milk and dark.
I did end up buying the pecan brittle because it was delicious. Other products looked also delicious and they have ice cream and drinks as well. They also have a decent sized cactus garden and a small m&ms store.
If you have nothing else to do then this kills a little bit of time and it is free. But please do not go out of your way to visit this place. You can get their chocolate at the airport too.