Just rented with them last week. My boys (6 & 11) looked great. My little boy wore his "Goofy Sailor Hat" with his tux and got his picture taken with Goofy in his formal wear.
We had gone to a formal wear shop here in CT to get measured thinking that that would ensure proper fit. Well, the local shop was not very good at measuring and Cruiseline Formal called me at work the week before the cruise to get everything straightened out. Once we got on board, my jacket was too large, but our stateroom host arranged a quick exchange for the correct size. If you rent for children be advised that they do not have extra children's sizes on board to make last minute changes, so you need to get the measurements / sizes correct.
Have a great time!