I was recently on the Constellation cruise to the Baltics, during July. I stayed in cabin 7208, aft..what a treat. It was concierge, and totally back aft. No noise from above. Also I booked it again , but on deck 8 for next year again. I liked CC class. Some wouldnt think its worth it, but it was the little things, like the towels, flowers in the room, special concierge items on menu that made it special. I noted that the difference for me for an 11 day cruise would be about 200 between a concierge and ocean view. For 200 not bad.
As for cost, 14 day was $7500 cabin cost..to the baltics.
Hope this helps.