We had cruised earlier this year on Majestic Princess (a sister Royal-Class ship to Discovery) and loved the experience. But as with Majestic, we had some issues, many related to the Medallion app (note: the actual Medallion itself worked flawlessly).
Medallion app- absolutely useless on embarkation day.
1 - it removed us from the "green lane" when we arrived at the port. We then closed it and reopened- and voila! Back we were in the Green Lane. Very frustrating.
Room attendant - we had a lovely deluxe verandah room on Deck 9 (Dolphin), midships. Quiet, nice, and our steward (Warlie) was fantastic (and of course we left him a generous tip). Room - the room is a bit "tight" by cruise ship standards, but served its purpose well, and we fully enjoyed the room.