I think dealing with chronic pf is like a peeling an onion. Something works for a while, it peels back a layer, then it stops working, and you have to try something else (not necessarily something new) to get to the next layer. I was surprised, but homeopathy worked for a while. I couldn't do even basic stretches until recently -- 7 months after diagnosis of pf (the pf had actually been festering for many years before diagnosis). But now I can stretch and do PT exercises in a warm water pool, let the jets of a hot tub massage my foot, achilles and calves (heat used to kill me), and gently use exercise equipment like the cross trainer, leg press and leg curls. It's all low key, but it increases circulation, strength, and flexibility, and that helps with healing pf.
I have been using the FootFlex too and it helps. For me, it is a much more effective stretch to bend the toes up while doing the basic runners stretches. Also, it keeps my knee on the pf foot straight, which it tends to not want to do, while I stretch. The FootFlex is a very simple device; therefore, I think it is overpriced. But if you feel better when you use it, well, that says a lot. Best of luck to all.