Sue, I had clients who wanted a small, informal hotel or B&B, not expensive, on/near the beach in San Juan for one night prior to a cruise in '98, and I booked them in the El Canario by the Sea hotel. It looked nice on their website (sorry, I have forgotten the address, but you could search on google for it), and it worked out ok, but they were disappointed - cleanliness standards were not quite up to the bigger hotels. Location was good, right on the beach, and the size was fine. Had they been willing to pay a bit more (price for a "deluxe" with 2 double beds was $99 then), they might have been more satisfied.
So far that's been the extent of my experience with small hotels and B&B's there.