The American Cruise lines are just appalling -- I spent a week on a Princess Lines boat and they pay their(mostly far eastern) staff a pittance and expect the customer to supplement this by their $13 per day bit. Whereas they say this is shared with the staff, the staff member I spoke to on Princess Lines said the majority goes to the senior people and the service staff see very little. They move the staff around frequently so they don't get organised to do anything about it.
I will NEVER darken their door again!!