Evie - Additional thoughts on aft staterooms:
If you sleep late you may not want the deck directly beneath the adult pool area - they shove around deck chairs fairly early in the am - if you are a light sleeper it might disturb you. Of course, coffee is only 1 deck up, but then there's room service ...
Deck 7 and 6 should be quiet and convenient to everything - some posts have mentioned "soot" from the engines may accumulate on the deck chairs and balcony at night so dust off before you sit, however we've never had this problem, though it could be unique to Spirit class ships. Carnival Triumph was not an issue -we were #8448 on deck 8
As you move down from deck 8 to deck 4 the overhang (roof over your balcony) becomes greater and the depth of the balcony increases too. If it rains you'll get wet on deck 8 less on deck 7 and so on ... deck 4 is covered or "protected" this most." You'll get sun during the day but when its "directly overhead" you are very well shaded.
Deck 4 allows you to hear the ocean and can be quite romantic and soothing with the water wooshing past as you travel to your next port ... did I mention it was also romantic!
Best $ you'll ever spend. Were in #4228 March 06