Different strokes for different folks.
As far as why SCC vs Hotel Coz right next door.... for us it is about the clientele. At SCC there are nothing but divers. At Hotel Coz there are families, lots of non-divers, and lots more people. At SCC the staff knows your name from Day 1. At Hotel Coz that would be impossible. We don't hate kids, but we don't want to trip over them running around the dock or the pool or the locker areas. No problem with that at SCC.
Ditto at meal time. There are only the people staying at SCC who are there for meals. I don't know what the big deal is... Breakfast is buffet and yes everyone lines up, but the line goes fast as it is just the people staying there eating. Lunch is served around the time boats get back, and is off a menu, so food is not buffet or cold. You get hot food. You don't have to rush to get lunch, you have time to rinse off gear and go shower and change if you want, as we always do.
Rooms... yes, our first time there we got stuck in a not-so-perfect room towards the street, but the resort was full. Every trip after that we got a good room, and last trip we got an oceanfront one. Maids are wonderful and room is always spotless. What more could you want? No tv, was that the real problem?
Dive op.... yes, they have a system and our first trip it took us the whole week to figure it out. But it works well. Boats... we have big camera gear and like the big slow boats with the huge camera tables. I also like the head on every boat. That way I don't have to pee in my wetsuit. I've done the smaller boats in Coz and it is hard on cameras. Trust me, I know.
Shore diving... just the best in Cozumel. That is all.
We had stayed at 6 different places before we tried SCC. Some big and fancy, some tiny and rustic. SCC fits right in the middle and suits us just fine.