I was surprised at the lack of diver input to site selection but there just are not many bad dive sites in Cozumel. But we really got to liking having the convenient and affordable option for an afternoon single tank dive with Dive Palancar. I will probably miss the Occidental Grand.
Awap, having a set schedule does offer an advantage in that you can be sure of getting to sites that you enjoy. If the Tuesday dives are to sites that are not your favorite, you can schedule a trip to the mainland. I have only dove from the Allegro or maybe the Grand one day. We went wherever we went.
I don't know whether that dive shop goes to Maracaibo, Barracuda, San Juan, Eagle Ray dive etc but I am happy with the diver input process.