Here is a brief report on my 10-day trip. I tried to eat at the best places around. For the most part, I found the food lackluster, though ceviche and fruit drinks were very good everywhere.
El Grano De Oro. This is by far the best restaurant I ate at in Costa Rica and the only one that was on par with fine dining in America. Interesting menu with good execution. Good service. I highly recommend.
Emperador at Royal Corin. Some surprisingly good dishes -- e.g., octopus carpaccio and caprese salad (made from fresh local mozzarella). Some duds -- e.g., grossly overcooked pasta.
Don Rufino. Hit and miss. Good cocktails, interesting menu. Some dishes came out well (e.g., gazpacho), others did not (e.g., overcooked roasted chicken).
Nene's. Simple, decent food. Recommended by my hotel, but nothing to write home about.
Soda Viquez. Even simpler, decent food. The fish in garlic sauce was quite good, but the rest was bland and boring.
Cafe Orchid. A nice place to have good coffee with tasty desserts.
Morphos. Decent all around, good service. A good lunch bet.
Laggus Restaurant at El Establo. A step above typical Costa Rican food, but nothing special. A good dinner bet.
Sofia. I liked the hearts of palm salad, which was exceptionally well presented. Everything else was unremarkable. Interesting menu, but I didn't think the execution was so great.
Taco Taco. I didn't like the Yucatan chicken tacos.
El Gran Escape (Quepos). The menu looks like that of a tourist trap, but the quality of the food was good. Fresh fish was prepared well; tortillas were homemade.
The Marlin (at the park entrance). Much better than I expected given the ultra-touristy location. I enjoyed everything I had here. Ceviche is a particularly good bet.
Kapi Kapi (between Quepos and the park entrance). Sometimes touted as the best restaurant in town. While that may be true, I wasn't very impressed with anything I had except the key lime pie, which was perfect to my tastes.
El Patio de Cafe Milagro (between Quepos and the park entrance). I enjoyed banana-macadamia nut pancakes for breakfast, though I thought they could have been moister. For dinner, I was underwhelmed by everything I ate. One big issue: I felt everything was seriously lacking in salt.
Pizzamail. The pizza is genuinely quite good. Definitely go here.
Marisqueria Corcovado. Ceviche was fresh and good. The seafood plate (called "mariscada") was phenomenal in size and scope. It had a whole fried fish, a lobster tail, jumbo shrimps, clams, octopus, little shrimps, mussels, a whole crab, and still other types of seafood I couldn't quite identify. All the seafood was overcooked to my tastes, but local tastes may be for meatier, chewier seafood. If you're very hungry, order the mariscada.
Soda Carolina. Probably the best typical Costa Rican food I had in Costa Rica.