The resorts I've been to in those areas recently (the last few years) are:
Dominican Republic (Punta Cana) - Colonial Majestic Hotel - this past holiday season
Mexico (Playa del Carmen) - Iberostar Tucan - holiday season ~3 years ago
Both are all-inclusive, and both are very kid-friendly (don't know if that's a plus for you or something to avoid). Of the two, the Colonial Majestic was in my opinion the superior resort. The staff is extremely friendly, the accommodations are excellent, and as Ron said the food is amazing. We didn't venture off-resort and from what I saw on the ride between the airport and resort there wasn't much reason to. The Iberostar Tucan (also nice, not to slight it) has more options off-resort if you're looking for that, from a nearby "downtown" to more significant excursions. When we were there a few years ago the beach had been extremely eroded due to a recent hurricane and extremely poor engineering management by other resorts along the beach (placing sandbags to protect their portion of the beach caused shifts in the current, which in turn eroded more of the beach). I hope by now that has been rectified, but if beach time is important to you you'll want to clarify the situation.
That's about all I've got. I'd recommend either option for a vacation (can't speak as much to the photo opportunities as I wasn't there for photography.)