I think the hotel is probably quite popular with the kinds of people who would otherwise be renting an Airbnb to stay in Luquillo. It's an area without much in the way of hotels. The negatives seem to be focused on the $17 parking and the $25 resort fee (which provides a $25 lunch credit that probably isn't too useful, because people are generally out and about during lunch hours), but if you treat those fees as part of the cost I imagine it's a fine place to stay. There are some comments about dampness and HVAC on TripAdvisor (and there are some reviews that look paid) but nothing stands out as outside the norm for a Fairfield. The pool area actually looks quite nice.

Fairfield Inns don't tend to get much traction on FT (or even on TripAdvisor etc) because they are generally run-of-the-mill offerings without much to say about them. I wouldn't read into the lack of reviews.