I just returned from a week long trip to CR. I dove 2 days at the Catalina Island area with Aqua Center and I can't say enough great things about them. Great Equipment, Great Divemasters, Great Boats. The first day 4 of us went out with one divemaster and I was really impressed on day 2 when they added a second divemaster for our group of 6. Previous posts about viz are correct, 30-45' are the best you can expect. However, when you see white tip sharks, rays, eels, and huge schools everywhere you really don't think twice about it.
http://www.aquacenterdiving.com
http://www.aquacenterdiving.com