"Six pack" is a term that's familiar and used for the small boat operators. Reality is most are "eight-pack." Yes, the high-end of the "valet diving" shops are fantastic... and one of them is my personal first-choice, but they aren't the best choice for everyone. Not everyone wants to pay $80-95+ for a 2 tank trip. Not everyone wants to have the dive shop rinse and store their gear, provide towels, fruit, water & soft drinks, SI's at beach clubs, have steel 95s, 100s or 120s, etc., etc. There's no shortage of dive shops in Cozumel. It's one of the few Caribbean destinations that I've been to that has such a vast selection of shops to choose from, regardless of where you decide to stay. Most places in the Caribbean that I've dived, your dive shop is decided by your choice of accommodation. The resort, condo complex, time share, or villa community has it's on-site shop. Choosing to dive with someone else adds cumbersome logistics to your vacation. In Cozumel, if you stay anywhere from town and south, you can pretty much choose any dive operator on the island and get pier pick up/drop off. It's almost impossible to have a dive vacation in Cozumel and not find your perfect combination of accommodations and dive shops. The downside is that as I recall, the first Cozumel dive vacation can be difficult to plan. Sooo many options and it's tough to sift through the cheerleading for various shops and finding which shop will really be YOUR best fit.
Definitely decide what you want in every aspect of your diving experience, then look for the shop that can check the most number of your boxes. The leg work is well worth it. Cozumel is a fantastic dive destination. If you can get through the selection process and make your best choices, you will surely be back again and again, and never be disappointed.