I would say that if you are an experienced skater and really want to skate you should bring your own skates and skate on advanced skating time when own skates are required and there is more space.
The rental skates are really lousy plus the skating rink on public skating times is so full of beginners that you really don't have a chance to skate. The people are actually falling on each other.
The skating rink is not good anyway (ice is too soft, even wet and bumpy), the rink is pretty small and I assume you are not even allowed to do any jumps. Anyway, our little figure skaters (the other one competing, the other one beginner) like the chance to practice even in caribbean, which has been the reason for choosing RCCL :-)