We have done many maiden/ inaugural voyages with RCCL. We expected some glitches, but all turned out well in the past.
Booked Quantum of the Seas along with our daughter's family approximately a year and a half ago. Prior to the sailing date whenever it was time to reserve something for the cruise I was unsuccessful doing it on line and with a RCCL representative on the phone. The common answer was "try back in a couple days", your account is blocked. Prior to sailing when I was unable to print my documents your representative told me there must be a problem with my printer, this was not true and caused me to waste a lot of my time.
Being a diamond member does not mean much on the Quantum. You must book a suite or have a gold card to eat at Coastal Kitchen, use the sun deck near the Seaplex, special seating in the Royal Theatre and certain elevators.