Claire, Here are my mixed feelings!
Pro's- easy sale as far as paperwork, sorting products, figuring out profit,etc.
Con's - price of dough is $12 to $15 dollars, right? Each tub makes 4 dozen cookies. I think that's pretty expensive. Your profit is $5 a tub. If someone doesn't want to buy cookie dough, for whatever reason, you've lost the sale. I would combine this with a t-shirt or pizza kit sale for maximum bang for the buck. If you are in the Northeast, Joe Corbi sells both cookie dough and pizza kits. And I would guess other companies have this combo too.

Our preschool has done cookie dough for years with good success.

It's not terribly expensive, you have limited choices which makes the selection and ordering process easy, and once you bake the cookies, it's gone so you might want to buy it again in the future. Just consider: it's a refrigerated product so the preschool always schedules the sale in the winter when the inventory can be distributed outside. Since it needs to be picked up that day, it's a good choice for our preschool because every child is picked up by an adult who can carry the tubs to the car.

How do they work out? We are considering a cookie dough fundraiser but have gotten mixed signals from other parents... so love some hate any experiences out there?