The 5227222-6: It mounts in a panel bulkhead using a front-side nut and also has through-hole solder tails for PCB attachment — a dual-mount approach that lets you secure the connector to the enclosure and the board simultaneously.
The nickel-plated zinc body provides the ground reference and corrosion resistance for the panel-mount environment. The isolated feature means the connector body is electrically isolated from the mounting panel, which matters when you need to break ground loops or float the shield.
The bulkhead mounting feature (front-side nut) lets you install it from the outside of the panel, with the nut tightening against the panel face.