I have used Aetrex for about 4 years. I had mild plantar fasciitis from a summer of tennis in flat shoes. I have relatively high arches. I went to a runners' store (Florida) where they put me on a treadmill and analyzed my foot with a computer which suggested their highest arch support insert. They are about $40 a pair, are stiff with a soft covering, and have worked very well. I replaced them after 2 years, maybe waiting too long to do so.
I have found I do not need them when wearing Keens as the support is outstanding in them (for my foot).
My suggestion is have your foot analyzed at a runners' shoe store in order to get the insert that matches your foot. There are many types of feet - I have the "American Athletic" foot type with high arches, wider at the front, narrow at the back. It's why most Italian hiking boots will not work for my foot (too narrow) but Lowa and Keen are ideal.