I stayed for one week, the rest of family for two weeks and they just loved Las Casitas Akumal. You have a private beach which is excellent if you are looking for a quiet place.
The snorkel is just amazing, you feel so close to the nature. At least per day you could see three turtles, rays, and diverse fishes.
The service is also a key point, our maid was called Maria such as nice lady, always taking care of us =)
The negative point, all the shops and restaurant are expensive. There is a supermarket in akumal beach but the price are incredible high. Therefore, I will suggest to drive a couple of km to buy all the groceries that you need.