How well does this memory foam mattress isolate motion for couples?

Very well. It scores 8.5 for motion isolation, landing at the quiet end of the field, because the deep plush memory-foam top smothers movement on contact and the solid foam core has no springs to carry it across the bed. Transferred movement measures as low as 1.93 on the meter scale. For couples where one partner tosses and turns, one side stays largely undisturbed while the other shifts.