Tubs do not feel anything like they do when water is in it. When you sit in the tub empty you are sitting with your body against the contour of the tub. When you sit in the tub full of water your shoulder blades and your butt are what touches. The deeper the tub the more buoyant your body becomes. The Archer is 19" deep, the Concorde is 21" deep. The deeper tub full of water is a lot more comfortable. Hope this helps!!!

I sat in a Kohler Archer drop in and the end where your head rests is more rounded than many I have looked at. Why more manufacturers do not make rounded headrest is beyond me. The sharp edge digs at the back of the (my) head - not comfortable.