I disagree about Aqua Safari; They're a good dive op depending on your preferences. Been diving with them for about 10 years and know their DMs well. Unfortunately they do have larger and slower boats which means more divers but I don't always consider that a bad thing. If weather is bad I'd rather be in a larger boat plus the larger boats have heads which smaller boats usually do not. Sucks getting caught in a storm and having no protection from elements on some of the smaller boats.
I've never had any of my dive times limited by them. Most of my dives averaged an hour or slightly longer. No 45 minute dives..
Aqua Safari also does not take out snorkelers, not sure where that came from? They would only stop at Park Royal if they had to pick up clients there. Are you confusing them with the previous dive op at Cozumel Palace which was Aqua World? Two very different operations!
A little background, Aqua Safari was always the on-site dive op for Cozumel Palace until it was taken over by Aqua World. Aqua World is a huge, commercial/impersonal dive op which has very large boats and mostly inexperienced divers. Very recently, Aqua World was kicked out of the place and Aqua Safari was brought back in.
Aqua Safari also does have one small boat, the Belinda which is limited to 8 divers. It leaves a half hour earlier than their larger boats. You may want to look into diving on the Belinda if you dive Aqua Safari.