All-inclusive means that food & drink (including alcohol) & activities are included in the price. We were lucky & got a 40% off deal through cheaptickets.com, and we paid on $180 per night for both of us.
Since the hotel is fairly new (openned in Feb '06) and it was low season when I went, there were not many people there at all. I did not have to fight for a beach chair, palapa, or anything. The pool was practically all to myself. Enough activities are scheduled through out the day to keep you busy also.
The only downside is that there is NOTHING around the hotel in walking distance. If you want to go anywhere else, you will no doubtedly have to book a tour or a car through the hotel, which may be expensive. You might want to consider renting a car from the beginning and drive there. Xcaret & Xel-Ha are not too far away from Puerto Moreles (20-40 min maybe). Cancun is probably 30 min away and I'm sure staying here is much cheaper and less crowded than the hotels there. (I did visit one 4-star and I couldn't even get a full-length beach chair cuz the pool area was so packed.)
