A main advantage of diving in the east, is that the operators can go north or south, depending on the conditions, tremendous flexibility.
I have only dived with Ocean Frontiers, the best land based operator I have used. You can do 5 dives per day on Tuesday and Thursday, as they offer night dives on those days.
This thread has me thinking, I'm due for a return to Grand Cayman
That is very true, but I don't want to suggest that only East End dives ops have opportunities to dive other areas of the island. Cayman tourism likes to advertise "365 dive sites" one for every day of the year - and there really are a lot of options around GC and also the sister islands.
The dive ops on the west side of GC can go to the north wall or the west dive sites or they can head south, depending on the weather. The west side reefs are sometimes overlooked because the corals and walls are not as dramatic as the East End or the North Wall - but there are some very nice dives on the west - and you often have the best chance of calm weather on the West Side. The best shore dives are also on the west side. There's often lots of sea life on the west reefs and some great wrecks, too.
One of the most memorable dives that we did during our vacation last year was on the Oro Verde wreck. We had not visited that site in a long time but we had so much fun on that shallow dive. The wreck is even more disintegrated than I remember, but there was so much life on it and all-around! The weather was perfect and the lighting was gorgeous and it was really a nice dive.