DDE is worth it if you plan on eating at sit down venues.. you save 20% on food and alcohol, but and not to bring this discussion back up, in 2008, they will add an 18% gratuity on your bill. So, in essence, if you planned on giving the server a 20% tip, Disney has handled that for you by adding an 18% tip on your bill and all the math is done for you. If you choose to leave additional, you can, but it is not required. So they will take the 20% off the bill and add back 18% for the tip.