Careful not to mislead. That was such a blanket statement, I have to comment. It is incorrect for you to state that SAS shoes are not suitable for persons with PF/Heel spurs. I indeed have PF and heel spurs and am getting great results with SAS shoes. I have three different pairs.
Yes, The insole that comes with the SAS Freetime walking shoe was insufficient for me too. SO, as I have stated over and over, I removed them and replace them with the red walk/run Sof Soles replacement insoles. I am having GREAT results with this combination.
SAS shoes' REMOVEABLE INSOLES are very much a part of the reason I can, in good conscience, highly recommend the SAS Freetime walking shoes. I have no financial interest in SAS or Sof Soles. It's just that I am getting great results combining these two products.
I still have a way to go, but these products, along with a few other PF maintenance diciplines, are helping me to be much less of a 'hobble' and much more a 'get out and about' kind of girl, than I was just a couple of weeks ago. I haven't even had a cortizone shot yet, though my ortho has offered. (However, now that the pain trend seems to be greatly reversed, I may very well benefit from a shot. I haven't decided yet.)
I have had PF and Heel Spurs a about a year now, and after that much time walking in pain and continually re-injuring sore feet, the reversal of the pain trend is simply WONDERFUL for me. And seems to just keep getting better everyday. This reversal of pain started when I got my SAS and Red Walk/Run Sof Sole replacement inserts.
Birkenstocks are obviously great shoes (and inserts) but they just may not be for everyone. SAS is a good alternative for many who don't want to go the Birks route.
Best regards and I hope you sell a lot of shoes,