My wife and I just got back from a 7 nighter aboard Mariner. I will go as quick as possible through everything:
Embarkation: We went touring around LA the day of Embarkation, so we arrived to the ship 2 hours before sailing and flew through in less than 5 mins.
Stateroom: We had a Jr. Suite on deck 10, and we were very surprised at the size. We've been in Jr. Suites on other RCI ships and this one was by far the biggest. The Interior decorations looked original, but in good shape and I could really care less if the carpet isn't modern looking. The wife loved the huge walk-in closet. The bathroom was fine, but the shower curtain was a bit clingy. The balcony was a good size (2 chairs, lounger and a table) The table wobbled, but nothing that a few folded pieces of paper didn't fix.
Huge closet, nice flatscreen TV, lots of room to sit, big balcony. Close enough to the elevators/stairs, but not a lot of noise. Under the Portofino restaurant, so there was no noise at night.