We stayed at both the Mayan Palace and the Grand Mayan last March. We started out at the Mayan Palace for the first week but were upgraded to the Grand Mayan for our second week. We thought this was a great perk at first but we soon found out that it was just the hook to get us to attend what they call an "Introductory Breakfast" which was in fact, you guessed it the dreaded "Time Share Presentation" complete with a lying pushy salesman by the name of "Johnny Mac". We got up and left after breakfast when the B.S. began. Never lie about to an old sailor who was stationed at the same you claim to have been stationed at Johnny.
Anyway the Mayan Palace is a nice place but it is probably the oldest of the complex. They claim it to be 5 Star but it's 3 Star at best. It was neat and clean and the staff were great but the furnishings are old and worn and unless you are an owner your suite will face the new construction area and it can be a bit noisy during the day. The bathrooms are smaller and there are no tubs, just a walk in shower. This could be an issue for families with small children. The balconies are small and there is barely enough room for a couple of chairs. The living area is a good size and has a good size kitchenette. We had to get the maintenance staff to come in every other day to repair faulty appliances (toaster, coffee maker etc.) I'm thinking that if you're an owner you get better amenities. They have a very nice pool area but it's quite a hike from the complex. The grounds are well kept and quite lovely. You can access all the other complexes quite easily along the pathways and everything is well marked. It wasn't a bad place it was just old and tired.
The Grand Mayan is big step up from the Mayan Palace. Large modern suites with large bedrooms and large balconies with a small pool on each one. The living areas are large with newer modern amenities. The kitchenettes are a good size with much better appliances than the MP. The bathrooms are large with jacuzzi tubs and large walk in showers. The pool area is a short walk from the complex and it is very nicely laid out. If you are not an owner you will not likely get an ocean view suite but even the suite on the other side have a pretty nice view and are far enough away from the construction area that you don't get the noise or the dust. The Grand Mayan is rated as a 5 Diamond but 4-5 Star would be more accurate.
There is a shuttle service that will take you all over the resort complex and even out to the front gate if you are planning to use the public transit system.
The resort itself is quite nice overall but it is a bit remote. If your vacation plans are just to hang out and relax by the pool this is a great choice. If your plans include exploring Bucerias or Puerto Vallarta it's a bit of a trek into either of these places by bus and cabs can cut into your vacation funds if you don't budget for them.
Once again and as always this is just my humble opinion and 2 pesos worth.