Hi, I've just moved to CT from New York. So far only 4 dives here.
It depends on your point of reference. I've dived the great lakes and NY, so find Cape Town warm with easier current conditions. Visibility can vary from terrible to fantastic. Wrecks can be as deep as you like from 20m (60 ft) to 120m (350 ft). Reefs are generally shallower. Often the boat will do an early morning dive to a wreck, followed by a mid morning dive to a reef.
I enjoy wrecks so this is paradise to me. They seem to be in good condition and offer good penetration if you are so inclined, equipped and trained.
Boats can vary from a DM watching your every move under water to a water taxi that drops you to do your own thing. I am more of a water taxi kind of guy, but you can find what you need. I've seen plenty of seals but only one small shark. Apparently something bigger is around, but you don't really see them.
I dive dry because I have a dry suit. The boat I used was about half dry, half wet. if you have an imperial rig that is in PSI and feet, you will need to become comfortable with the conversions to metric.
PM me when you get here, my wife and I would be happy to do a Shallow dive with you when you're ready. I AM NEITHER AN INSTRUCTOR NOR A DM so if you prefer I can also provide you with some names. I dive with underwater explorers and like them a lot. Unfortunately their website got hacked and deleted so what they have now is rubbish while they rebuild it.