It depends on what your interests are. We were there in 2003, so it may have changed since then. In 2003, Hell was a small area of rock formation, a post office (from which you can mail your friends and co workers a post card from Hell), visit the tourist trap shop, be greeted by a cashier that says "what in hell do you want?," and pay way too much money for trinkets. Also, a seedy bar is in Hell.
I'd be inclined to spend extra time swimming with the stingrays. The turtle farm; beware. We were led to believe it was a sanctuary and breeding project to assist in the repopulation of the sea turtle. In actuality, only a portion of the turtles are released; the remainder are raised for food.
Your call; personally, I'd pass on Hell.