How is the edge support when sitting or sleeping near the side?

Edge support rates 7.8 out of 10, with sinkage measured around 2.5 inches near the perimeter, firmer than average. The dense 2,400-coil system carries support toward the edges, so two people get usable width. One honest caveat from an owner: because there is no rigid foam edge rail, sitting right on the corner can feel like it gives slightly, so sit toward the center of the side rather than the extreme corner.