We are in NV right now and I would stay at the Grand Mayan for the reasons above. However, don't write off the MP pool. Yes it was reduced in size by about 30%, but it is still huge when compared to some of the other resorts in the area. If it is just the two of you, the MP pool can be more relaxing as most of the louder activities and family gatherings seem to happen mostly around the GM pool complex. The MP pool is right down on the beach and is sometimes a quieter option.
They are currently demolishing the one wing of the MP (jackhammers are going strong outside my Grand Luxxe room right now @ 6:30PM). Hopefully the demolition will be complete by your stay, but the construction on the replacement building may just be getting underway. Play it safe and book the GM and you'll be away from the construction noise and still have your choice of the two pools.
Curt