I have stayed at both several times and there is no comparison between the beaches. Punta Cana offers beaches that are the most beautiful that I have visited. They are wide and stretch as far as you can see. Plenty of trees offer shade back away from the water, and there is a constant breeze off the ocean which keeps the temperatures much more pleasant. The water is very calm and conducive to water sports and snorkeling.
We have stayed at the Bavaro Beach Resort three times and it is a fantastic complex that has much to offer. Punta Cana doesn't offer much off the hotel complex areas, as it is still being developed. Day excursions and trips are offered, and I have heard that many are very good.
All in all, I would (and have)recommend Punta Cana to anyone who wishes to visit a beautiful beach, with great weather and activities to do. We will be making our fourth trip here in June/July this summer. We will be staying at the Hodelpo Bavaro Resort and will be sure to post a review when we return.
Enjoy your trip, you'll love it!
Fred