For being in 9-ft seas I wouls ssaay the ship is fairly stable, but not like Oasis was. I definitely feel it moving, but we are going top speed through the Atlantic (but the seas have calmed down as well). It is not a bad motiion, though. I am not hearing reports of people getting seasick, you feel the motion, but it is NOT too disagreeable.
The crew is VERY happy on this ship, as i just reported. Their crew area is amazing. I don't know why no cruise line will allow me to take pictures of the crew area - its dumb because it iss so nice.