Agree with both Karen and Wendy about the advantages of the Bernina presser foot #72. In addition to the comments I previously made about the marks on the #72 that make ruler work even easier, I have to say that it also eases any concerns about the damage to the needle bar (an issue for the Westalee foot as well as the #96 foot that was designed specifically for the Q20 and Q24). My understanding of the repair issue is that, if damage were caused by the Westalee or #96 foot, Bernina would not service the damage under the warranty because those presser feet had recognized issues and Bernina warned against their use. Of course, if you never have a bad day and always lower your presser foot and then your needle, you won't have damage, but I was not willing to take that chance even though I was fortunate to win a Westalee presser foot a year before the #72 came out. I tried it a few times, but knowing myself, it was like playing Russian roulette, the day would come when inadvertently I would do the wrong thing, resulting in damage that would not be covered by Bernina, so I waited until the #72 foot came out.
As for the #72 being designed for the Q20/Q24, it was not. It was designed specifically for the domestic Bernina machines. When Janome came out with the ruler foot for domestic machines, many of us were hoping Bernina would do the same. I've just searched my records, and I had sent an email to Bernina USA back in 2013, asking them to consider a ruler foot for the domestic machine. The person who responded agreed to forward my request to the factory at that time and I received confirmation shortly afterwards that it had been sent. Westalee also came out with their ruler foot, I'm sure lots of Bernina lovers deluged Bernina with requests for a domestic machine ruler foot, I probably was not the only one. When the Q20/Q24 came out, it had the #96 ruler work foot available as an accessory for the Q20/Q24. Since those machines are designed to accept many other Bernina feet, it was widely assumed that if the darning foot from the domestic machine could be used on the Bernina longarm machine, then why couldn't the #96 foot be used on a domestic machine? It could not because the chances of hitting the needle bar if the presser foot was not lowered first when starting the machine was too great, so Bernina could not sanction its use without liability, hence the warning that if damage resulted from using the #96 or any other ruler foot not designed for the Bernina, resulting damage would not be covered under warranty. At the beginning of 2016, there still was no official release date for the domestic ruler foot, but it was widely known that it had been in testing. At Bernina University 2016, in New Orleans, the #72 foot for the domestic machine made its debut and the rest is history. Many of us are very happy owners of the #72 ruler foot for the domestic machine.