Fountain is great for a quick, "familiar food" meal with burgers, hot dogs and such. They have a good tuna sandwich that was a pretty fancy dish that DH and I split. Fountain is also an ice cream shop so they have great desserts. It is table service, and has a walk up counter for ice cream. It is a bit "on the path" because it is not enclosed, lots of walking by traffic.
Fresh is a more traditional buffet station restaurant. We haven't tried the food but I've heard it is very good and it looked nice when we passed by on our last stay.
Picabu is a cafeteria style place - go through the line, order your stuff and what isn't ready immediately is brought to your table. They also do to go, so I did a few mornings of going down there for breakfast and taking it back up to the room. The kids meals were plenty of food for a regular breakfast, DH and I split the adult breakfast entrees.
There is also a counter service on the lobby level where the bar is in the evening. They had coffee drinks (latte and such) and the best regular coffee I had on vacation. They have a fix it up bar with coffee syrups, real cream and the works. The also have the best cheese danish I've ever eaten. They didn't have them every day but OMG they were really good when they had them.
Even if we don't stay there on our next trip I'll be going by there for my large coffee to go and a cheese danish.