My insert and boots with the self massage and regular exercise seem to have kept my feet pain free for over a month now. Today I'm going for an over night backpacking trip on snowshoes and don't worry about pain....
The Birkenstock insert, I tried two of them, is agreed not a good option.... they need to put the arch support much further to the rear than where it is. I am leery of Birks for any thing other than 'casual' wear around the house not more than 4 hours in them.... I used to work in them but my feet hurt after half a day, even though they were delightfull for the first half...