I'm not a huge fan of Punta Cana, but my wife likes it there. I think the benefit is that given that all of your food and alcohol is included in the all-inclusive resorts, a trip to the DR can actually be a good bit cheaper than many/most areas or all of Florida. There also is something to be said for the all-inclusive treatment. I simply wouldn't go and really lie around and drink all day if I was paying $10 or $15 each for cocktails, whereas I really do take advantage and likely drink at least 6 or 7 drinks daily at the resorts, whereas I'd never do that stateside. The food is also included, so you can always get an appetizer or dessert with your meal without regard for cost. In my experience, the food has ranged from decent to very, very good depending on which resort that you're in. The snorkeling at the nicer reefs is kind of neat, fishing is available for a fee of course and some of the tours are actually fairly educational and enjoyable (we've been on snorkeling tours, farm/country tours, cigar shop tours and rum distillery tours). I don't golf when I'm on vacation (unless one of my brothers is there and they encourage me to go), but you can also golf there and most of the resorts have their own small casinos as well.
Like I said, the DR isn't really my cup of tea, but it's very accessible and relatively inexpensive if you're into that sort of thing.