Jeff, unfortunately I have not heard the ISW-4 but I did see a preproduction example at B&W's hq. It did appear that they had put a lot of work into building a very high quality sub and not just a woofer in a box that could be stuck into the wall. I would always choose free standing subs over in-walls for numerous reasons, but if the sub(s) must be in the wall then the B&W is worth looking into along with the JL, BG Radia and velodyne in-walls.
