A lot of it depends on how "aggressive" a diver you and your companion are. The one resort I return to on an annual basis is Cocoview. That is in part because my wife loves the laid back easy diving. Minimal currents, lots to see in shallow water, easy shore dive with tons of different stuff to see and on the shore dives you can just poke around without a divemaster rushing you. The chain from the resort to the wreck out front makes it a no brainer for even a first timer to be confident in navigating to and from the resort. Yeah, it is a great place to dive your brains out and build confidence. Perhaps the best part is the design of the boats. They have a hole built in the center of them so if water is a bit rough (rare on the south side of the island) you can come up a ladder through the hole and you don't have the issues of timing when to grab a rocking ladder off the back of the boat.
On the other hand if you don't mind some current look to Cozumel. Virtually all dives are drift dives. It must be one of the swim through capitals of the world, lots of cool structure and probably at least a dozen dive ops with fiercely loyal clients that are convinced that ther favorite dive operation is the "best in the world".
I go about 3 times a year on dive vacations. One of those is Cocoview, the others are anywhere. This yr it is Cocoview, Palau (2 weeks, one on the Aggressor and one with Sam's - I'm checking our both live aboard and land based to determine which one my wife will prefer next yr. gotta love research!) and Hawaii (we did the Big Island including the night dive with mantas and also saw the largest turtles I've ever seen).
Comparing Scuba club on Coz, and Cocoview I don't see how you can lose. I would lean a bit toward Cocoview just because the shore diving is better and more diverse but the same could be said about the night life of Coz

. I have seen more "big stuff" at Coz but it is harder to stop and study things due to the current. Like choosing between chocolate or vanilla shakes, you are about to have a fun experience, either way.