Is this mattress good for couples?

Yes, on two counts. Edge support scores 8.4, with firm-end sinkage, so the reinforced pocketed-coil perimeter stays solid when you sit or sleep to the side, keeping the full width of a queen usable. Motion isolation scores 8.5: the 1200 wrapped coils localize movement. The honest caveat is that the thin 1.75-inch top absorbs less surface jolt than a deep plush bed, so it is solidly better than average for couples rather than the absolute quietest.