I would definitely recommend spending the extra and get at least a balcony cabin. We cruised on a similar class Carnavel ship last year and did this. There are some places on a ship you don't want to be, so look at the deck plans.You don't want to be next to or above/under places like kitchens, bars, theaters, casinos, engine rooms, elevators, etc.
We went all out and got a cabin on the 10th deck, or Panarama. It was in the front of the ship and about as high up as you can go. We just walked down the hall and the waterslide and swimming pool were right there. We also had a bank of elevators nearby that were at the main atrium. The balconies are small, but the privacy is great. It was good to order room service for breakfast or just sit down and watch the sunset at the end of the day. If you book at the same time and have adjorning cabins with friends, they can take the partitions down to connect your balcony with theirs. If you are lucky and get a corner or rear cabin, then you can get a bigger balcony. I would try to get a balcony cabin on the Panarama, Lido, or Verandah decks, in that order. Some of the suites were a deck above us on Spa Deck, but I think they had large picture windows instead of balconies.