This may be a little late, but I'll put this in for anyone looking for more information about diving with UTW at the Grand Palladium. I was there last year and I did 4 days of diving... two ocean dives with UTW and two cenote dives with Playa Scuba (Klaus). The folks at UTW were nice. Since the dive sites were so close (5 min boat ride), the whole diving experience was a little different than I've done before. In the set up at Grand Palladium, the divers suit up outside the dive shop and carry all their gear across the beach, into the water and on to the boat. As the boat heads to the site, the divers set up their tanks, and before you have a chance to sit down, you are at the site ready to go. After your dive, you go back to the beach and do your surface interval back at the resort. You can even go to the beach bar and have a quick lunch (although the beach bar food is pretty bad). When its time for the next dive, you meet up again at the shop, walk back out to the boat and do it all over again. Its not a bad set up, especially if you have family waiting for you at the resort. You can do your SI with your non diving family and the diving does not take up the whole day since it is all pretty quick. But, on the other hand, you sort of lose that part of scuba diving that takes place above the water. I felt like I didn't meet anybody since there wasn't much "hanging out" on the boat (granted, I only did two days with UTW). When we hit the land for our SI, everybody scatters and does their own thing. I kind of missed spending the morning on a boat with new diving friends, just relaxing in the sun. The way its done here isn't bad... its just different.
One other thing ... I chose to dive with Klaus at Playa Scuba for the cenote dives because I heard good things about him, and his prices were almost 1/2 of the cost to dive with UTW. Klaus was great and the cenote diving was definitely the highlight of my trip. BUT... I've read that other shops are not allowed to pick you up inside the resort grounds, and that was the case for me. I had to carry all my sh!t out to the highway, where I had to wait 20 minutes for Klaus to pick me up in his pickup truck. The palladium is freaking huge, so this is really big pain in the ass if you are bringing your own gear. If you dive the cenotes with UTW, they come right to the dive shop. Something to consider if you are staying at the resort and are looking at other shops for your cenote dives...
All in all, I would dive with UTW again if I go back to the grand palladium. The diving was decent, and I enjoyed it. I know what to expect and what not to expect, so its all good.