I've been to San Juan a few times. In OSJ, my wife and I like the following:
- La Taberna Lúpulo. A cozy "American" bar with an extensive draft beer selection. Also have nice small plate menu. Nice, open-air place to hang out for an hour or two to get out of the sun or rain. 151 Calle San Sebastian.
- El Jibarito. Neighborhood restaurant not far from Taberna Lupulo. Good, cheap local food and drinks. If with a group, order a few things to share. Glorified street eats.