So I just got married at the GBP Tulum beach location in June of 2014. We had 55 guests. We had the beach ceremony at 5:00, dinner in the mediteranean restaurant at the Coba side, and then a poolside party.
So my honest opinion - and here goes.
Don't get married here. I did my best to have a good time, but they were so unorganized, it was really stressful, and the whole point of us booking a destination wedding was so that it wouldn't be stressful. I think if you have a small wedding of less than 20 people they probably do ok, but for groups larger than that, I would recommend going somewhere that doesn't have 10 weddings a day. The coordinator, Maria, was horrible. They don't care about the small details. It's just an in-and-out process for them. Our meeting with her only lasted a half hour, she didn't go over everything with us, and then the day of the wedding when things were happening that we didn't know about, she just kept pointing at the contract we signed and saying "you signed the contract, it's in the contract". You don't get very much time with her. And she's not detailed or organized. They were over a half hour late picking me up at my room for my ceremony. Maria didn't even write down the right room number, the driver was waiting outside the wrong building. She didn't apologize. She told me I wasn't where I was supposed to be, and that she had been phoning me, which is funny because I was in my room with about 6 other people and the phone didn't ring once. Then she told me it was because there was an issue at the beach location (which there wasn't, the rest of our guests were there, she just was coming up with excuses).
The ceremony location was beautiful. We brought our own fabric and chair sashes - the stuff the resort has is quite tacky and they only have white. So if you want any extra color you have to bring it yourself. The flowers were beautiful, no complaints there. All in all the beach location was stunning - it was super hot out so I wasn't too pleased with the fact that my guests were waiting outside for an extra half hour because I hadn't been picked up....but the beach ceremony was really great.
Our dinner in the restaurant - the food was actually delicious, but the service was terrible. We had 55 people. This is a normal amount for them to serve in a night. First they wouldn't let some of our guests in because they were wearing shorts. No exceptions. They were actually really rude about it, and Maria was no help whatsoever. Again, she stood there pointing at the contract. Eventually one of our groomsmen had to leave the dinner to get pants for those guests. Maria did nothing, which I thought was horrible given that she's the wedding coordinator. I had hoped that a wedding coordinator would be there to help things run smoothly.....not the case there. We had people who were done their dessert before others had even gotten their entree. We had to ask the servers 3 times to please serve the head table first. There was no organization to it at all. They brought out the cake in the restaurant when people were still eating. It was just a mish-mash of events.
The poolside party - this part was actually really fun. They decorated it really nice with lights and tables, we had a DJ, our guests had a really great time at this part of the wedding.
The photographer - also not very good. He was in and out as quickly as he could be, literally. He didn't give any direction for any of the photos, so a lot of our photos are just people standing around, not looking at the camera, etc. One of my good friends is a photographer and she was there, so I was very happy that she had managed to get some good photos for us. But the photographer the resort provided, just not professional. And the quality of the pictures was just so-so. And they are very expensive.
The reason we booked the Bahia was because it was large and very family friendly. I had actually stayed there before about 10 years ago and loved it. But honestly, I wish we would have gone with a smaller resort, that cared about their guests. The GBP I think they just get sooooo many weddings there now that they just don't care about the level of service they provide anymore. It was one of the worst customer service experiences I've ever had, and I've stayed at a number of different resorts in the caribbean before. It was hugely disappointing.
So there's my two cents. Hope it helps.