Cbm32, your not-great experience with the dive op illustrates why there's no such thing as the best, or the top 10 best dive ops on the island. Like others, I'm pretty sure which shop you're talking about. There are people that have been diving with that shop for years and have had consistently good experiences. Great even. From your post, what happened and why seems pretty clear. You chose a "big machine" dive op and were staying very close to a cruise ship terminal. You were new to the shop. Don't know how many dives you originally booked, but if it was 3 days, that would be a factor too. When I read your post, I thought, "Of course that's what happened." Given your experience with that shop and your dive experience, I can understand why you decided to go with someone else. I don't know if you talked to the shop about your concerns, but if you had, it's likely they would have been able to accommodate you. On the other hand, I can understand why you'd be happy with Tres Pelicanos and say as much. No hidden agenda there, imo. Just the truth of your experience, which btw, isn't unique, but isn't the only experience that shop can provide.
This last high season, a newer diver from around here made a first trip to Cozumel and stayed at Hotel Cozumel. Once back, the diver posted on social media that "Dive Paradise is the BEST shop on the island!!". Heh. Well, they found something that works for them. Good enough. Sadly, the diver has a shiny new DM card and is proximal to lots of new divers here, and will likely be telling these divers that "Dive Paradise is the BEST shop on the island." His top ten list would have just one shop, Dive Paradise, a big machine that's been around a long time, and does a fine job, I'm sure. BEST shop has a much to do with the diver as it does the shop, imo.
Mediumone and others that liked my post, Thank You. For the record, Deep Blue offers afternoon dives much like most of the other shops on the island. There's a minimum number of divers needed to make a boat. Used to be 4, I think it's 3 now. I've gone out in the afternoon with just a DM and myself, but that was a result of the circumstances. I've been out when it's just myself and two other clients many times.
To the potential Deep Blue cruise ship diver: I can't keep straight which cruise terminal is which, but Deep Blue will tell you how to get to them. You'll probably be asked to take a taxi to either the shop or the caletta. I think the downtown terminal is within pretty easy walking distance of the downtown dock and/or the shop, so they might suggest walking if you want to. (10-15 minute walk?) You'll need a taxi to get to the caletta if that's where they want you to go. There are several factors involved, but you'll likely go to a Palancar site for an 80 foot dive. If nobody on the boat has been yet, it'll likely be Palancar Gardens, which is a beautiful site and a great first dive of a trip. The second dive will be 50-60 feet and which reef depends on the conditions and where others on the boat have been that trip. Because they leave later, they're offset from the other ops, and as a result I've only run into other divers on the reef a handful of times, maybe less. With the other ops I've been with, running into other dive groups happened regularly. I have UW video of about 30 divers all in one spot. We were a group of 6.
Finally, if you're a newish diver or new to the diving there, a private DM isn't a bad thing, and will cost about $50. It's not that the dives are death defying, but it's cheap peace of mind if you're not familiar with the area and the diving. Also, when you talk to the shop, let them know what you want and your comfort level. If they don't know, they can't make it happen. Same advice for any shop you contact.
If you like diving, you'll love Cozumel. Have fun with whomever you choose!!