I have experience with both the Mercure and the Duque de Wellington. I'm going to Santo Domingo on Saturday and will be staying at the Wellington for one night before heading to Juan Dolio. The Mercure has always been my favorite hotel in Santo Domingo. I have stayed there 3-4 times a year over the past 3 years. My reason for not staying there this time is this. They have raised their rates for a suite twice. First it was $90. Then it was $105. Now it's $135! And they deny that they've raised their rates. I'm not an idiot. I have receipts for all the times I've stayed there. I know what I paid. Granted, the Mercure is a lovely hotel in a fabulous location. It is clean, well kept and the staff is very nice and professional. The management, obviously, is another story. When I told her that I had paid less before she said she would check to see what staff member charged me less and make them pay the difference! I then informed her to cancel my next reservation. She said fine and that was that. No acknowledgement that she was losing a long-term guest.
I stayed at the Wellington once a couple of years ago, and it is adequate. It's not the Mercure - nor does it pretend to be. And yes it is a place where many gay tourists stay. But then again, so is (or WAS) the Mercure.
Trust. We don't bite!