The Blue Diamond is a gorgeous retreat. We stayed in a Patio Junior Suite and it was very comfortable. It was also incredibly private. The whole resort, in fact, is extraordinarily private. You arrive to the front lobby, which resembles a shrine. From the time we arrived, to getting checked-in, to walking the long path to dinner, it took us over 2 hours to see any other guests!
The images online don't make the layout clear. The lobby is about 1.5 kilometres from the beach. The Jr Patio Suite are about halfway, so a good 750m to walk in the morning. It is a gorgeous walk. The grounds are immaculate, lush, well-groomed and maintained, with occasional animal highlights (tajones, iguana, caiman, etc). We loved the privacy, and it often felt like we had the resort entirely to ourselves.
There are two beautiful pools above the beach. In our time there, we never saw a single person use the pools. We also saw only a couple of couples brave the wavey water. The wind was very high every day, and the seaweed was intense. They worked hard to clear it (by hand, they don't have any beach grooming machines, but they were overwhelmed. The pools were kept cold, which is fine, but the cold with the heavy wind made them unusable.
The food was exceptional. We went as a vegetarian and a vegan. The vegetarian had excellent options at almost every meal. The vegan had fewer options. Breakfasts and lunches were real highlights for both of us, but main courses got pretty bland.