GOOG it and read some reviews, esp Trip Advisor, and in addition to the glowing reviews give the middling reviews a read for an alternative set of opins.
https://www.tripadvisor.com/Hotel_Re...Peninsula.html
It is supposedly adults only, which is a plus...
Not clear what is included in the 'all inclusive' aspect.
There are dozens of resorts in Cancun and more further south in Playa del Carmen through Tulum aka Riviera Maya; the difficult part is comparing more than a few or wading through all the reviews and 'noise' on each property.
Have not been to Sun Palace, but it seems decent, as do many of the other dozens in the area. We have had stays at a few, and also over on Cozumel, but nothing in past couple years, so my opin would be old news, as the staff/chef/situ can change considerably depending upon Gen Mgr, bean counters and current staffing, in our experience.
GL, mD