If you are referring to a CC! as Concierge class I'm pretty sure you hit the nail on the head other than the wee extras you get appies ,flowers etc. the rooms are the same to the best of my knowledge .....and I can tell you from personal experience that the rooms in 2A and 2 B's are the same but the balconies are about 6 inches smaller for those aft CC's.than the 2'sA&B. (measured them with my croc's.) But I have not been in a SV....
The biggest draw back to the aft cabins is the distance from the Rear Elevator and Stairwell. It's a long way when you forget something
The aft cabins have no where near the balcony benefits of the M class
"Note" that thumbs down got in there without my approval and I can't seem to make it go away
& then I did and it's gone now lol