As previous posters mentioned, it is a better value to rent your points and use the cash for the cruise. However, remember to keep in mind that renting points requires more work and also brings along what can sometimes be a large risk component. Plus, even if you use a company like David's, you will not get all of the money for the rental, until after the renter takes the trip, 50% up front, 50% at the time of the rental.
From personal experience, there is more to "value" than dollar amount. We always just use the points to book the cruise because we find renting to be too much of a hassle and risk. Others will tell you exactly the opposite and have good valid reasons for their argument.
The bottom line is do all of your research way in advance, and remember that the points are yours to do with as you see fit, even if you choose not to wring every last dollar out of each one.