DR1, I have been into Punta Cana marina several times and, although I agree with you on the quality of the marina, hotel and restaurant, I do am not sure that the channel is 10 feet deep. Also, the entrance to Luperon is a piece of cake compared to going into the Punta Cana harbor. Although Punta Cana is better marked, it is narrow and twisting between reefs. The marina is fairly new and I do not think that the chanel is marked on most charts.
However!!! If you are making the run on water from Luperon to Samana to Boca Chica and your vessel has a draft shallow enough to get into Punta Cana, I highly recommend a stop over there. It is one of the few ports in the Dominican Republic where you are not hustled and pay a premium (about double the legal price) for fuel, the beach side restaurant over the water with the glass (or plexiglass) floor inserts, allowing you to look down into the cristal clear, night lighted water is a very nice atmosphere to go with an excellant meal.
And, the last time I stopped over there, June of 1998, while my wife and I were enjoying all of this, the yacht was being fueled for Samana, and my captain, fishing off the dock, hooked into a very nice Snook.
The dock crew are helpful and friendly and do not try to rip you off. What more can you ask when you are crusing?