I've never cruised on Royal Caribbean, I've only cruised on Carnival, and only once did I book a guaranteed cabin (I will never do that again). I love the Riviera deck because it's really quiet, albeit far from everything else, but I don't care. The one time I booked a guaranteed cabin, my husband and me ended up on the one of the higher decks at the very front of the ship. I hated it to no end because I could really feel the ship's movement and everytime we were reaching port there was a very loud noise that would wake us up early in the morning.
An upgrade to me is not being moved up to a higher deck. An upgrade to me would be inside to outside, outside to balcony with no obstructive views and balcony to suite.