How well does this mattress isolate motion for couples?

It isolates well with one honest caveat. Motion isolation scores 8.3 out of 10 with a measured 5.15 m/s2 peak, and the 1000 pocketed coils each compress on their own rather than passing movement across the bed. The caveat: natural latex is inherently bouncy, so it carries a touch more movement than a deadening memory-foam top would. It still beats most hybrids, but if dead-still motion control is your single top priority, a memory-foam bed will edge it out.