How responsive is this mattress for changing positions?

Very, the most responsive bed in its group, and the extra-firm build is exactly why. Total bounce travel measured a touch over 10 inches, well above the field, because with only an inch of comfort foam the 875 pocketed coils drive a lively, springy surface. Recovery is quick too, springing back in under about 1.5 seconds. If you change positions through the night or want a buoyant feel rather than one you sink into, this delivers it.