I was at the Iberostar this April and I dove mornings with Tres Pelicanos and afternoons with Dressel.
First I will say is that the Dressel bashing is unwarranted particularly from people that have likely never stayed at the resort or are competitors. People can have opinions but now I am starting to see dubious advice given. This forum is very hostile towards Dressel. If you actual dove with Dressel and chatted with the repeat visitors, you would find people that have dove with all the ops that were recommended in this thread but for various reasons have come back to Dressel.
Second I will say that diving with both ops, while staying at the Iberostar, has pros/cons for diving with both ops. I dove with both ops for various reasons in order to take advantage of the pros both offer. If you don't think Dressel has any pros you are being closed-minded.
Lastly, and I will admit this is atypical because I have visited Iberostar/Dressel before, they are more flexible than this forum would have you believe. On my last dive as we were walking off the boat, we bumped into our favorite DM who we did not get to dive with. He immediately said no way one more dive with me. We said we were done AND didnt want to go to the site they were headed too. He asked where we wanted to go, I named a site they never go on their schedule. Guess what, we went. With a group of 6...
I dove this same non-scheduled site with Dressel on my previous trip...and it wasnt me that asked.
So let's stop the Dressel bashing because it's unprofessional and its triggering my fairness gene to defend them when I see dubious claims being made against them.
With all due respect, since I am the only dive shop posting in this thread, please kindly point out where I have "bashed" Dressel. For the record, we have a completely different business model, so they are not my competition.
I have posted only factual information, no personal opinions about them. There is a difference.