I cruise solo so price is always the main factor. I am never in the cabin except to sleep, shower and change. Also, I am a night owl so by the time I go to bed, I am usually (a) well lubricated
and (b) exhausted.
I book inside guarantee (cat. 1A) unless I can get a really good mini-upgrade to a specific cabin. I am partial to Riviera because there are two decks of cabins between my cabin and the action. Also, Cat. 1a's on Riveria are usually at the very front or back of the ship and there is almost no foot traffic in the hall. It has been my experience that I can hear the noise in the hall more than I can hear the engine, anchor or feel the ship's vibration.
Lastly, living in NYC, one learns to sleep through outside noise.
In truth, I don't care where the cabin is as long as it is on a ship.