also at one point i owned 4 panavise bases. i didn't like the vacuum mount base so i gave it away but even before this i owned three bases, two screw-clamp mount, one weighted mount, and at least one of every vice head (two standards, one long, one centric long, one pcb with every length of pcb arm)
typically when i use a panavise and i'm doing anything that's not trivial soldering, i'm using more than one base