I stayed in Mexico for my honeymoon and it was the best holiday ever.
We were in a resort near Cancun- play del carmen and the hotel was called Riu Tequila.
It was all inclusive and you could use restaurants/facilities at 3 hotels and they shared the GORGEOUS beach- shallow, warm water and loads of sun loungers etc.
The food at the hotel was amazing- especially breakfasts where there was anything you could possibly dream of...
any kind of fresh fruit
any kind of freshly mad fruit juice
meats, cheeses, cereals, mueslis, yogurts, pastries, breads
freshly mad doughnuts
freshly made waffles
freshly made pancakes
any kind of syrup- maple, chocolate, fruity, coconut
cooked breakfast- bacon, sausages, eggs (poached, scrambled, fried, omlette) mushrooms, tomatoes, beans...
tea, coffee, milk, hot chocolate
WOW and I even lost weight!! Not sure how- must have been all the swimming.
I don't know how great it would be for kids but the pool was great and they organised water volleyball etc. No slides though.
The beach was 2-3 mins walk and there was a little bus thingy you could get on if you wanted too.
We went to Xel-Ha which you should google because it was amazing and you would all love it.
Only thing was we went in October and in the evening it was too hot to go out so after our meal we just lay in our room under the fan!