Just back from a week in Costa Rica -- here's a report on the places recommended by Chowhounders:
In downtown, we had a nice and inexpensive lunch at Mamma's Place -- sort of local Italian. Good garlic bread, excellent soup, sandwiches. Just off Calle Central.
In Escazu, we went to La Cascada -- very good steakhouse. The kabobs were the best of our three entrees, but the sauce that came with the "Cascada" tenderloin was also very good.
There is a one-block-long Chinatown in San Jose. We went to the only one open on Sundays (the big bright one -- can't remember the name -- across from a theater). Hot and sour soup (agropicante) was very vinegary. Other dishes were quite good and reasonable in size (a sizzling rice dish and a curried shrimp dish).
At La Fortuna (near Arenal), we had a good chicken dinner at La Chosa (downtown, such as it is), but even better and cheaper was La Posada, right across the street from the regional bus station.
Our last three days were at an all-inclusive resort (Paradisus Playa Conchal). The buffet lunches and dinners were good, breakfast was excellent, and of the a la carte restaurants, the Caribbean option was outstanding, and the Asian option not so great. Church's Fried Chicken at the airport was passable.