This is a topic I feel many shoe manufacturers ignore. I have very flat feet. Charlest, do you recommend either of those inserts for flat feet?
Many years ago when I developed severe Achilles Tendonitis, my physical therapist prescribed Superfeet insoles. He said for most patients, they worked at least as well as custom orthotics at much lower cost, so try them first.
He was right, and I've worn them in all my shoes/boots since (hiking, skiing, snowboarding, bowling, walking). There are several Superfeet models based on foot shape and activity. For flatter feet and some cusion, look at the Superfeet Copper. I have them in my hiking boots and bowling shoes with no complains. I also use the Green and Blue models for specialized needs.
I haven't tried the brands that Charlest suggested, and they may be just as good. I'd suggest going to a high end sporting goods store that carries multiple brands and try them in the shoes you'll be wearing. They're all a little different with respect to feel, so make no assumptions.