The problem with 3 point soft suspensions is the high centre of gravity which makes them wobbly and unstable. But if set up correctly where the arm and platter bobble up and down in unison when pushed, soft suspension designs do isolate very well in the audible range... except for ultra low frequencies (below 20 hz) where their low mass subchassis become very sensitive to subsonics like foot falls and truck in the driveway.
