IMO, Princess Captains Circle loyalty program is a joke when it comes to perks/benefits. We have cruised with Princess since 2010 and was surprised to see the CC didn't improve, even a little bit.
RCs Crown and Anchor Society and Celebritys Captains Club is a lot better especially for the top three tier levels. But when you reach the different tier levels (top three) with CAS and CC the extra perks/benefits are nice. But having said all of that, we are starting to see the CAS and CC start to eliminate/reduce/change some of those perks/benefits also. We aren't loyal to any one cruise line so we don't chase the tier levels (we book cruises for the itinerary, not the cruise line or the ship).