In case you do not choose your cruise by destination, ship, company or price, Cruise Critic have produced a table comparing the loyalty benefits you can acquire from sailing with different companies.
Here is the link: http://www.cruisecritic.com/blog/index.php/2013/08/19/cruise-line-loyalty-with-chart-break-down/
If you would like more detailed information, please visit their article which takes an in-depth look at what each loyalty scheme offers.
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