I'm a Chowhound from the San Francisco Bay Area. I got most of these recommendations from here, so thanks so much for the fantastic guidance!
KASALTA in Ocean Park: This place would make a nice pit stop for a picnic or a day trip. There's a great selection of by the pound imported cheeses (Spanish, French, etc.) and meats. The crowd seems to be mostly Spanish speakers, but this place is mentioned in guide books and had a visit from Obama in the past few years. We stopped in a few times, so here's what we thought. The filling in the pastelitos de guayaba y queso (pastry w/ guava and cheese) seemed to get lost. I much preferred two items whose names I don't recall. One was a guava filled triangle of pastry that I felt had more balance between pastry and guava, and the other was a cheese filled pastry log. Neither blew me away, but I'll admit to not being the biggest fan of these types of pastries. The chorizo wrapped in pasty dough was my favorite... a very flavorful pig in a blanket. The marinated octopus salad, in the deli counter to the left of the cashier, had tender pieces of octopus and was a good contrast to all the heavy fried items and desserts. The guava jelly roll was pretty good but one of us found it sickeningly sweet (not me!). The media noche, the sandwich Obama ordered, was pretty lackluster. It's swiss cheese, ham, and turkey with a pickle on a grilled sandwich. They get points for having freshly carved turkey, but the turkey was dry and not especially flavorful.
BEBO'S in Condado (they have another location in Cupey): As the waiter said, people come here because the food is cheap and the food is good. It's looks like it's in a converted Denny's, and the best things seem to be the daily specials at the back of the menu. My first meal here was at lunch. The roast pork mofungo was great and better than I later had at Cafe Manolin. Lots of spicing on the meat, and the plantains has a good pork flavor and weren't too dry. My second meal didn't work out so well. I arrived at about 9:30PM, and they were out of most of the interesting specials. A service error combined with my inability to communicate well in Spanish left me with a bad meal.
MANGO's in Ocean Park: This is a "safe" place for tourists, but there wasn't anything outstanding. I had a bacalao (salted cod) stew with yellow rice. It was very fresh tasting, but was underseasoned and didn't have a strong enough bacalao flavor. The rice and beans thankfully lacked the packaged/MSG flavor common at some other places we went to, but were a little bland. The chuletas (pork chops) were overcooked. The yuca gnocchi carbonara was a decent fusion dish. The gnocchi held together and were firm and flavorful. The sauce was really heavy (cream, i think) so it was good to split this dish with the lighter ones.
PAMELA'S in Ocean Park: Dining on the sandy beach was really cool, but you certainly pay for it. We started with conch fritters and corn fritters. There batter was good, but there was so much of it that we had a difficult time distinguishing the conch and corn fritters. The caesar salad had fried serrano ham on top and fried yuca as croutons. Good concept. The yuca was properly fried and we could have used some more of it. Our first entree was scallops with a lychee mojo sauce, served over mashed potatoes. The mashed potatoes were fantastic. The scallops were good, but could have used some more searing and the lychee flavor was so mild I could barely taste it. We enjoyed out second entree, grouper, also served over those delicious mashed potatoes. We also enjoyed our dessert, a bread pudding served with caramel ice cream. Drinks were ... mixed. They made great pina coladas, and we should have stuck only to the local specialties. Their $15 (!) patron margarita was awful--- there was salt on the bottom of the glass and it was so bad that we had to send it back. With two drinks per person, this cost us $70 each and, though good, I didn't think it justified the price.
JOSE ENRIQUE in Santorce: By far, this was the best meal of the trip and in a fun location. Everything was spectacular. We came here on a Friday night, and it took about 90 minutes to get a table once we put our names down on a list and they took our phone number. This was not a problem--- it's in a plaza with music, cheap and stiff drinks, and tons of people (90% locals, 10% tourists according to our cab driver). A good chunk of customers seemed to be regulars, so there was a really nice vibe to the place. We stared with the housemade longaniza with tostones. The longaniza was juicy and delicious. The tostones were fine (I've never had ones that I've loved, so that's probably a personal preference), but I liked them a lot with the hot sauce they provided. Wow, that hot sauce was so amazing, I later sipped a spoonful of it later in the meal. It's apparently sold in the market across the street. Anyway, the fried cheese bolitas were served on a guava paste and were phenomenal. The yellowish cheese paired well with the guava, and they were perfectly fried. The cangrejo (crab) served on some kind of plantain fritter were even better. Our first main, "empanada" filet mignon, was kind of like a beef schnitzel. It was well prepared and very tasty, but I expect there were more interesting items on the menu. Their salmon w/ squash ragout was great--- I'm not sure I've had salmon before that has such a buttery texture. The most surprising part of the meal was the simplest--- a side dish of avocados with olive oil, salt, and pepper. Maybe it's because they have a different type of avocado in Puerto Rico, but even after eleven years in California, this was the first time I really "got" avocados. The arroz maposteado (rice and beans cooked together) was savory and naturally flavored--- no hint of MSG. For dessert, we started with 3 squares of caramelized cheese topped with pineapple preserves, guava preserves, and one which I forgot. As with the bolitas, they really know how to pair cheese and fruit. The ice cream dessert came with 4 housemade ice creams: sweet cream, cream cheese, mamon, and brownie. And the server brought us an extra banana one too! The mamon came down to personal preference for that fruit--- two of us hated it, one loved it. I really enjoyed the brownie, but the banana was my favorite. We finished with a complemrentary shot of an anise digestif. Overall,, this was one of my best dining experiences and I highly recommend prioritizing this place. Their chefs really know how to bring out the natural flavors of their ingredients. Note that they're closed on Sundays and Mondays. We walked there from Ocean Park, and it was a $12 cab ride back.
LA BAMBONERA in Old San Juan: Based on another thread, I had the Mallorcas here. They're a sweet bread, and you have the option of getting them with or without powdered sugar. Pretty good stuff.
CAFE MANOLIN in Old San Juan: One of the more inexpensive and less touristy places in the area. The chicken mofongos were pretty good--- better mofongos than I've had in the states, but not as good as the ones I had at Bebo's. The chuletas can can, a deep fried pork chop surrounded by ribs and pork skin, seemed like a great idea, but it was pretty awful. I love big hunks of pork fat, but the meat was dried out and the skin tough rather than crispy. The rice and beans were pretty basic.
More to come in a few days ...