The All You Can Eat pass is a great deal. It costs $29.99 (you can save the tax if you buy it at the ticket booth outside the park, I am still not sure why they don't charge tax but inside the park does). We find the price is well worth it if we are going for the entire day. We go early enough that we get breakfast (usually served until 11 A.M.), lunch and dinner with some snacks. It includes drinks at the locations that you can get food from. We actually bout a souvenir sipper when we didn't do the all you can eat deal and they will refill it (normally refills are about $1) as your drink and you get more beverage. Of course you can also get bottled beverages as your drink instead.
NOTE: The wristbands are only valid at the major restaurants and there is an upcharge for Ribs, but if you want Ribs, get the Smokehouse Sampler Platter at Calypso Bay Smokehouse and you get Ribs on the plate.
One hint with the wristbands, go in at park opening, go to breakfast, then a show and you should be on a good schedule to go to the restaurants at the less busy times. (i.e. not normal meal times).
As for the food, it really is reasonably priced for what you get, but the wristbands make it an even better deal.
For example at Mam Stella's, I like to get the Sampler Platter, which includes penne pasta with Marinara Sauce, Eggplant Parmesan, Cannelloni (spinach and sausage) and a bread stick. The normal price is about $11.99. With the wristband, you can get this AND a side or dessert AND a drink every time that you go through the line. So while some entrees may seem like they have a side with them, they count as just an entree. And yes, you get one entree, one side or dessert and one drink every time you go through the line.
I also find the food at Sea World to be among the best of the various parks here in So. Cal. (especially when comparing it with other parks Counter Service). Although,
Disneyland is catching up in quality with their menu revamps.
Also, passholders save 10% off the price of the wristbands.