Cancun...
...bar none.
I never understood why American's want to go to a foreign country and have it be just like home.
I spoke with a number of developers and folks in the toursim industry while there and they said that US visitors far exceeded other countries and this is what they wanted.
Malls, chain restaurants from home, and pat the dolphin shows.
Skip it and go to Florida, if that's what you want.
We shortened our stay rented a car and spent the rest of the trip in Talum and Merida.
A truly appalling place.