We stayed deck 5 forward, almost at the tip of the ship. We felt heavy movement on a couple of nights, but the captain said we were in some rough waters.
All in all we all enjoyed it and booked the same rooms again next year. Me, my wife, DD 5, DS 3 and DS 10 months didn't get sea sick, nor did we take bands or medication.
We stayed on deck 5 aft on the Dream twice and we didn't find any issues with movement either.
You're going to hear all different reviews based on people's tolerances.