My favorite places are Costa Rica (Jaco Beach area) and Ixtapa / Zihuatanejo, Mexico for Bill fishing and snorkling...they also have a great night life and great restaurants, but very laid back compare to Cancun and Playa.
I also love the people and the beaches in Punta Cana...the DR is the only place I have dived...got certified there...so I really can not compare, but I loved the diving there! Sint Maarten / St. Martin is another favorvite...great beaches...great friendly people...2 Cultures...Dutch and French..great food and shopping...great snorkling...great night life and day trips to St. Barths, Anguilla, and Saba...