All pull changer is is currently the most modern and most used system on a Pedal Steel guitar, for many reason i would say. When compared to the push-pull system, all pull allows greater ease of adjustment and more choice. In a all pull system the raise and the lower are two separates systems accorded to You can have many choice on a push pull too but it need brainstorming session and hat trick to get the best results. All pull system is not tune in the same order than push pull (more logical). First is the string open tune (no pedals, no knee) with the keyhead; and the second step is the nylon tuning adjustement with pedal and/or knee engaged. On a Push-pull system you need to engage first the pedal or knee for tuning the string and adjust your open string with no pedals or knee using the screws behind the changer. It's two different technology with two different turn of mind (and certainly two different steel guitarist afficionados).