What are you looking to do? Walk the docks and look at boats? Or are you looking for a slip for your boat? If the latter are you willing to pay the freight for Newport Beach or similar. Or are you looking for low cost? Liveaboard or not?
It all depends. We could recommend dozens of marinas to look at and miss the mark without further guidance.
I lived in Newport Beach for ten years but kept my boat in Long Beach. Long Beach was less than half the cost of Newport Harbor.
David