This was my first trip to Cancun and when I go back I would like to stay at the Gran Melia again. First of all the hotel (lobby, rooms, pools, everything) is absolutely beautiful. The style is modern, not colonial. The sushi restaurant, the bar and hotel in general is very romantic. We didn't notice a lack of entertainment because we spent most of our time at the hotel in the huge pool and at the excellent beach. We did not try the spa or the golf course.
Every experience with staff was positive, they consistently offered excellent and friendly service. They were very helpful giving directions, helping us book our tour to Chichen Itza, and all the usual things a guest needs in a hotel. The location was great, with a convenience store right across the street for cheaper snacks and booze. Hop on the bus right on the street and 75 pesos and a few minutes get you anywhere you wanted to go in the hotel zone for restaurants, night clubs, shopping, and adventure. The buses run all night and every few minutes. It was very easy to get around.
As for the food, my boyfriend and I are vegan and were able to find good things to eat for breakfast at the Café Quetzal, from Nami, the sushi restaurant, and from room service. They were very accommodating of our special requests. We didn't try to the other restaurants, because Tempo seemed too gourmet for our budget, and a few others seemed too meat/seafood centered. The Mexican one never seemed to be open. We had the most delicious vegetarian sushi, pizza without cheese, and vegetarian spaghetti. The abundant fruit and veggies were pretty good.
My only complaint would be that the prices of things in the hotel's convenience store (bottled water, snacks, booze) is almost twice that of the convenience store across the street. But price variance is pandemic in Mexico in general, so if you care about getting the best deal you have to shop around. In a shop in the mall one guy tried to sell us earrings at "60% off" for "only $75 USD," by the time we left without buying anything he came down to $5 USD.