Is this mattress good for couples and does it isolate motion?

Yes. Motion isolation scores 7.9 out of 10 with peak transfer measured near 2.97 m/s2, so a partner rolling over or getting up is largely absorbed before it reaches your side. With no connected coils to pass energy sideways, the latex and support foam soak up movement where it happens, and the all-foam build is effectively silent with nothing to squeak. Natural latex is marginally livelier than memory foam, but the difference is negligible for sharing a bed.