I am going to have my wedding there (GBP La Romana) on October 2012. I like the hotel, and the prices are very reasonable! However, dealing with them have been a nightmare!!! It was mainly because of the Event Manager; she was so slow to reply and not efficient at all!! She was very nice and said yes to everything I wanted, but for God sake, she would take forever for any simple thing!!
Last week we found out that she was fired! (Wonder why??!!!) I just hope that the new event manager is better! I don't know yet who she/he is. I just wrote them an e-mail so that I can start coordinating (again) everything for my wedding.
Gran Bahia Principe La Romana definitely need serous help in terms of communication and directing you to the right person. It took several phone calls for me to get the right person that would coordinate the room reservations, but at the end it was worth it since they gave me a discounted room price for my guests (the hotel is already cheap, but I got it cheaper!!). So, I am happy about that! My wedding is for 200 people though, not sure how much that influenced the discounted price, but it doesn't hurt to ask for a lower price even if you are planning a small wedding!!!
Keep in mind that high season in Dominican Republic is December - April. If you plan your wedding for any of those months you and your guest will probably be paying 50% more for plane ticket and rooms.
Hope this helps!!