I see I was mentioned. Whilst I live and work in London we are in a suburb, which is actually in the countryside with forests and fields we are away from any noise. I am a light sleeper so " any" noise wakes me up. Deck 8 on the Magic we have never ever had an issue, in fact on these boards it seems often to be cruisers who hadn't been on deck 8 making comments. We have had inside rooms outside rooms and prefer deck 8. I would say if on the next release of cruises all decks all rooms were the same price ( ex concierge) everyone would book a higher deck and a verandah they know it's better. The one factor, is price. Cruisers choose Deck2 for vacation budget only. How much you are willing to spend. The higher the deck the less vibration and less movement you get. That's basic science. As Scotty on Star Trek would say you can't break the rules of science. The further you are away from engines and further away from the sea the better it is. Deck 2 being under the main entertainment and MDRs and above engines and close to dock walls will get more noise. Thrusters vibration etc. Movement wise the lower you are the more sudden and unexpected random movement is felt.Higher up the movement is ironed out to a gentle sway. The sudden lower deck movements coupled with being enclosed a low cause motion sickness. So if your ears detect movement but your eyes say I see walls, and your brain says walls do not move, you get sick. If you go higher look at the horizon and get fresh air you feel better. So Deck2 is enclosed and low near engines. There was mention of the laundry never book a room next to it, hot humid and used 24/7 and people speak loud there. All those who " love" Deck two also post how wonderful it is to get an upgrade to a higher deck. They know the higher the better. The reason to book deck2 is low cost, end of. TAs knowing your budget will sell you the benefits, they are sale people, a sale of a low cost room is better than no sale. The elevators are busy all ship. That is another false assumption, in fact in port it's the noisiest and most busy place. People on higher decks do not use elevators to Cabanas or the snack places ir soda station or pools or spa lower decks have to. In summary book to your budget, but posters should be honest and explain that you only book Deck 2 to fit your vacation budget, you are on the ship, you get the same food and entertainment, but higher decks are priced higher for a reason otherwise they wouldn't sell at that price. IE Alaska verandahs sell out very very fast.
I think some of it has to do with the individual as well - some people will be bothered by things that others aren't, just a fact of life. I did look up stateroom reports for the cabins we had last time, and saw nothing that indicated people were bothered by excessive noise at the time, but who knows. Some will like being low on the ship and not notice noise, and some will like being higher up. When we were on Deck 10 on the dream, I was worried we'd hear a lot of noise from the pool deck (and the pirate party on Pirate night), but again, we heard almost nothing, and the kids running through the hallways were the loudest noise we got. Fingers crossed our staterooms on the Wonder this April will be just as magical as the others have been! 
That is of course if we are all going to listen to "DISNEY FANTASY" cause you know price dictates everything and well those are the cheapest rooms on the ship and they are practically giving them away. 
So they must be terrible!
We had some friends who stayed on Deck 1 on the Magic last April, and they really enjoyed it. Said it made for easy on/off at the ports, and they loved the double porthole window they had. I don't recall any complaints they had at all!
I liked being close to the elevator as that seemed to keep the kids running in the hallway noise to a minimum because they couldn't yet pick up speed when they passed my cabin.
