Just returned from the Quantum and was a little disappointed considering the cost of this cruise.
The good : the rooms are stylish, understated and functional, with plenty of storage. Check in was very efficient, less than 30 minutes and our luggage was at our room by the time the room was ready. The indoor pools and hot tubs allow you to start your vacation immediately. By sail away at 4pm we were in the hot tub watching lady liberty pass by. My stateroom attendant was attentive but not obtrusive and very sweet.
The bad: dynamic dining is a stressful mess ! After trying to book seating 2 months in advance I could only secure late night times and with a 6 year old that was not practical. We tried to change our times while onboard through the phone, but were told we had to see a representative at the restaurant. We spent 40 minutes trying to change reservations and couldn't, so we just showed up early and were seated twice and turned away twice. Speaking to other guests they echoed the same sentiment. Once in the restaurants the food was good and the waiters were delightful and accommodating, but getting there is hit or miss. We only ate at one paying restaurant, Izumi. The sushi was average in every way but price. I've never paid $10 for a California roll before !
Beautiful room, spacious with good storage.