I agree that when you add in the option of sleeping on board the night before the dive trip, it works out pretty well.
I often recommend to divers from outside of SoCal that they consider one of the dive boats that lets them sleep on board. It is MUCH less expensive than taking the Catalina Express over to Catalina, paying for the parking, diving with one of our boats (although SCUBA Luv's King Neptune is well worth it since you will most likely get to dive with me, the infamous Dr. Bill), and paying the outrageous prices for hotel rooms here (at least during peak season).