Re: Push/Pull v.s. Push/Push
Electrically they're the same. Mechanically, the push/pull works by pushing it in and pulling the knob out.
The push/push toggles its state with each push. Kinda like the on/off switch of a home stereo.
The push/push has the advantage of ease of use, the push/pull has the advantage of being able to tell what position its in at a glance.