I honeymooned there in 2015. It was amazing. The fishing was great*, but check the seasons. When I was there we caught blue runner as bait fish, and then amberjack as the main catch. Some really large fish out there!
http://www.cancunfishing.com/fishing-calendar.htm
We stayed in the Riviera Cancun, right on the beach. The food was all included and simply superb. All drinks included, except wine at dinner.
*The fishing would have been great if I didn't suffer from horrendous sea sickness. $200 to puke my guts up for 8 hours, now that's value!