The only similarities are the parking. La Jolla Cove offers great kelp diving with Giant Sea Bass, large sharks and the occasional turtle when conditions are good. La Jolla Shores is a sandy beach with a looooonnnnnggg swim to reach the canyon, but well worth the swim. Crabs, bat rays, fish, moray and wolf-eels and jellies. Laguna Beach is more laid back with rocky reefs near shore, some reachable with a decent swim and some thin kelp. You will see the usual nearshore animals at every site with sea lions added near Seal Rock/Deadman's Reef.
In the summer you need to get there before sunrise or happen to luck out if someone is pulling away from a prime parking spot. Fresh water showers and restrooms are plentiful in La Jolla, not so in Laguna Beach. If I was diving coves other than Picnic Beach/Divers Cove I always brought a couple of gallons of fresh water on my dashboard for a warm rinse after diving.
Scuba Diving La Jolla
Deadman's Reef 12/30/2017. Laguna Beach scuba diving with the Sole Searchers Dive Club