We spent a week at MRBR, with 5 days of diving. There is almost nothing that could have been any better! The staff is the most genuinely friendly we've ever encountered; their default answer to any question is "yes" or "however you want"; frequently checking to make sure everything was just the way we wanted.
Rooms are spacious and airy, all amenities well thought out (there is even a drain hole in the shower soap dish so your soap doesn't get soggy!). We had a water-view room & I'd recommend that -- lovely to watch sunset from our balcony.
The only minor negative to be aware of is that Internet is expensive, slow/intermittent, and available only in the lobby.
The restaurant has a limited selection (understandable when food has to be shipped in from far away) but everything we tried was good. Breakfast buffet has a wide selection including house-made pastries, eggs made-to-order and pancakes. Special requests were cheerfully accommodated if the item was available. The open-air bar is a great place to visit with other guests.
The dive operation -- wow. First the shop: we each had our own cubby where the crew stowed our rinsed gear each day; we were responsible only for our wetsuits. Camera folks: you will have your own personal workspace complete with multiple charging receptacles, magnifying glass, chamois cloth, & pressure air nozzle for drying, plus lockable storage underneath.
Boats are designed for only a few divers; our max was seven, usually less. Longest ride to a site was about 30 min; most were much shorter. Fresh banana bread for surface intervals! Dive guides are local, expert, and happily tailor trips to divers' interests. I won't go into dive details since you can read them in the web, other than to say all superlatives are true.
Very few places make our "must-return" list; this is one of them!
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.