How is the edge support on such a tall bed?

Strong, scoring 9.3 near the top of its range. Loaded at the perimeter, the side holds around 4.23 inches of sinkage, with a foam-encased coil unit giving the sides far more firmness than a bare foam edge. On a 16-inch pillow-top this matters, since a tall plush bed with a weak edge feels unstable. Here the encasement keeps the whole sleeping surface solid right to the rim, so you can sit on the side or sleep to the edge.