Apart from No 4 the press, all these are cheap death clamps. Hydraulic press designs are far far safer. They are more expensive but what price do you put on safety? If one of these cheap threaded death clamps lets go slips or beaks and a spring gets loose you are potentially at great risk of serious injury potentially fatal. You want to avoid this at all costs. Get a hydraulic press stand.
I've got the last set and they are very dodgy. The hooks are at right angles to the threaded bolt so when placed on the springs they don't hug the spring. You basically get one point of contact on both springs. I yet have to discover a set with the hooks angled to completely touch the whole spring for a full grip.
