I returned from a weeks cruise on the Destiny a couple of weeks ago and thought that spending a bit more to upgrade to a cabin on Deck 6 would be an amazing "treat" however, you feel the motion of the ship a LOT more from higher up the ship, and would have actually paid anything to be downgraded to a deck 2/3 cabin!
It is inevitable that you will feel the ships motion from any deck, however, i would choose a lower deck cabin as it's more stable down below.
Regarding the crew, having spoken to a lot of them, their cabins are NOT part of the passengers cabins as advertised in the brochures and on deck plans. They have separate cabin and crew areas so they do not take up any passengers cabins so the amount of cabins you see in the Deck 2 deck plans are for passengers only.
Hope this helps!
