CABIN 1051, Deck 10, Promenade: I would say YES to the spa cabins but NO to cabin 1051. It is the last of the interior rooms and closer to the middle of the ship so I chose thinking I'd feel less of the ship movement. However; this room is right next to the stewards galley for the deck and every morning at 6 a.m. I awoke to the banging of various carts being pulled out.
The photograph of the cabin on the Carnival website is it, I was wondering what the rest of the room looked like but the answer is there is no more, lol (besides a bathroom and closets.) There was TONS of closet space, and with our luggage stored under the bed we had plenty of storage room.
The spa ocean view's were sold out very quickly so I think getting one is rare. I almost went with a spa balcony but they were $500 more and despite several calls I never was able to con anyone into giving me one at a discount. $500 is about what we spent on our sign and sail for alcohol, gambling, the steak house etc. so I am happy with my choice to stick with an interior (plus it's nice and dark in there!) Whatever you choose, if you like going to spa's then yes yes yes, get a spa room on the Splendor!