Great all inclusive resort with fun and friendly staff (Ricardo was always helpful). Perfect for our vacation intent which was relax mode around beach\pool with no kids. Would definitely go back in a heart beat.
Grand Paraiso is situated at the end of the Iberostar complex housing the other resorts along with a golf course, tennis courts, convention center, small shopping area with food, gym, spa, etc. Colored wrist bands are given and worn during your whole stay indicating which resort you're from. Grand Paraiso has access to other resorts, while other resorts do not have access to Grand Paraiso.
Can't speak to activities available since we chilled the whole time, but here are thoughts on other parts...
Rooms - clean and comfy as a hotel room should be, plenty of space, large bathroom, patio area with lounge chair and swinging chair, stocked mini fridge with snacks (chips, nuts, chocolate)
Beach - no complaints sitting on the lounge chairs under umbrellas. Waiter comes around to take orders of drinks (and food if needed). Felt prompt. Never got in the water, but the water line looked rocky.
Food and drink - standard fare. Buffet (no reservations needed) open for breakfast, lunch, dinner. Reservations needed for dinner at the specialty restaurants. Taco joint down in the shopping area that's worth a visit for street style tacos. Room service too if you want to stay in.
Tipping - same as anywhere with good service. No need to change to pesos, dollars are just fine. In fact, if you're planning on staying at the resort only, there really isn't a need to convert currency.
Gym/Spa - worked out some to help with the all inclusive drinks and food. Small gym on the Grand Paraiso property. It was sufficient, but got a bit warm. Bigger gym with fitness classes down in the common shopping area. Also in the area was a large spa with sauna, steam room, jacuzzi, and pool.
Pools - three pools - indoor pool, outdoor tranquil pool, and outdoor main pool with beach view and swim up bar. Only partook of the main pool. Has lounge chairs and cabanas all around. Again, waiters come around to take order. Activities (pool volleyball, relay races, etc) at certain times of day set up by the staff.