Booking- easy.I liked being able to pre-book tours and Spa sessions in advance, on the internet.
Boarding in Barcelona- great! Handed cases over to staff who placed them on a conveyor (after checking tag had cabin number on) and entered large, cool terminal building. Up an escalator to a hotel style reception desk to register credit card and collect 'sign + sail key card'. Then they take a photograph so when the card is swiped for any payments on board, your picture comes up on the screen. Entered ship on deck 3- the Atrium. Not quite as spacious as advertised, OK its 7 or 8 floors high but only near the lifts. Disappointing decor, green motif on lights strange and altogether neither cutting edge modern nor classic ship decor.
Amazing organisation with 4,500 passengers to embark- also true in ports we visited!