We just got back from a week at GBP Coba and enjoyed our trip. I wouldn't say its the best nor the worst place we've been.
The Good : The staff, grounds, rooms, buildings, bars, pools are all excellent.
Average : food at buffet and a la carte restaurants are average, but remembering the thousands of people they're serving, they do a good job. Dont expect filet mignon or lobster here. The front desk staff do need to be trained a bit better as well.
The Bad : Beach is over 1 km from most rooms, so dont forget anything or want to go to bathroom, its a long way back. The size of the 3 hotels is massive, takes forever to get around. If you're a beach lover, this isn't the place for you, artificial walls to break the waves are approx 40 ft out to form little pools of water, like wading pools, 3 ft high, so you cant go out much, great for kids and elderly people i guess. 1st resort i've been to in past 10 years that charges for deposit box !
Also, had a sore ear from swimming in pool, no problem, but Doctor's visit was $260 (ouch !), guess they know people have insurance.
Absolutely no advantage of Golden Club except you're guaranteed not to have your room near the highway. The bus from airport went direct for everyone at our hotel. You get an extra a la carte, but again, not gourmet food here, so do you need to pay extra?