We stayed here for a week for a wedding and loved it. http://www.realresorts.com/The_Royal_Playa_Carmen/
You fly into Cancun and take a 30 minute shuttle. Good photos here: http://www.realresorts.com/The_Royal_Playa_Carmen/Photo_Gallery/
and check out the virtual tours of the rooms. It's accurate.
It's all inclusive, but the food was actually quite good. There are different styles of restaurants and I don't think there was one buffet. It's adults only, so there is no problem with other people's kids being annoying as shit, and there are bars everywhere you turn around. There's not techno music blasting by the pool, and there are even smaller pools around the resort for more secluded hanging out. Beach was great, it's private just for the resort, has nice lounge chairs, and little mattress cabana things if you want. Waiters will bring you drinks at no charge and don't expect a tip, although a tip will ensure more attentive service. We gave our closest bartender $20 at the beginning of the trip and he made us awesome drinks all week and served us before others. The room was also wonderful. Huge bed, two person bath/hottub looking out over the beach, balcony, huge bathroom, in room bar (Vodka, gin, whiskey, rum, tequila, all sorts of sodas and mixers, and snacks no charge), room service is also included, although not as good as the restaurants. There is a town there that our friends explored, but the resort was great and I've lived all over Central America, so I wasn't interested in seeing the local culture in a tourist town. Our friends were also staying at the sister resort next door, which was like $30 cheaper a night, and was everything that is wrong with all inclusive resorts. Festering buffets of burgers, hotdogs, and fries, watery drinks, large redneck families with no control of their kids, dj yelling into the mic between each song, etc. Even the towels and the beach chairs were crappy. The food was seriously dogshit that their place. Their place was called the Grand Porto.
I'm 27, she's 26 if that makes any difference to you.
We recently stayed at the Cove in Atlantis in the Bahamas for a trip I won through work and had the opposite experience. Everything was covered by my company, but the food was worse (even at Bobby Flay's Mesa grill down there) and it was SO expensive. Two salads for lunch was $90, before tip and drinks.
My opinion would absolutely be to find a resort that is all inclusive, just do your homework before going and find a place that has decent restaurants. It made all the difference. You also know going into it that you've spent $2k on your vacation or whatever, and that's pretty much all you're going to spend, rather than budgeting $2k, but ending up spending another grand because shit was more expensive than you thought.