I used CenoteXperiance a few weeks ago. Took the 7 a.m. ferry across from Coz, they picked me up at the dock. 2 tanks at dos ojos went great. If you e-mail Nico with your preferences I think he would accommodate you.
A third for CenoteXperience with Nico and Martin. They were so great that I want to leave a detailed review but can't figure out where the best place is... hopefully this will suffice! I'm sure there is more than one great dive op, but I at least want to share my experience with them. Of note for folks, I was staying in Tulum but even though they are based in Playa del Carmen they came and picked me up... just contact them if you are interested.
My experience with CenoteXperience ranks as amongst the best dive operators I've ever used. I used Tres Pelicanos on Cozumel, based on reviews here, and they were OK. CenoteXperience blew them out of the water. They gave incredibly thorough dive briefings before each dive: describing the cenote and the path we would take, any specifics to that dive or cenote (instructions, signals, etc). Of course the day starts with some general cenote-specific dive instruction. It was my first time diving in cenotes and I was 100% comfortable and had no issues whatsoever. They are very safe: asked for questions after every briefing and before descending, and just before descending ask for everyone's air level and even personally checked my tank configuration (not that I need it but I appreciate the extra thoroughness). My friend doesn't dive so I was solo, and Nico took me out for 3 dives the second day even though I was the only one signed up - I really appreciated that! Both Nico and his brother Martin are also just great guys to dive with, which is always a plus. Other small things: I get cold easily and they brought a hood for me even though they don't rent them, and they didn't charge me for Nitrox though I'm not sure if that is standard. Lastly, the gear is good - no problems at all.
Overall, I was really impressed and had such a great experience with these guys - if I was considering cave certification, I would without question take a course from them, and if I return to dive the cenotes one day in the future, I will without hesitation use them again! I can't say enough nice things about these guys!
A last note, initially I was a little bummed out about the price of cenote diving - it certainly costs more per dive than if you do 10+ dives off Cozumel (i.e. get into a package price). Now that I've done it, I actually think these guys are really reasonable in price - cenotes usually have an entrance fee, there's a bit more driving involved, they bring snacks/lunch/drinks, and the whole process just takes more time and effort than your usual reef diving.
