They've got a terrifically supportive heel cup, and good arch support (both of which work great for me, though probably not for everyone). They are very thin under the bottom of the heel, so they only raise the heel a couple of millimeters.
They also have a prominent bulge under the metatarsals, which is something that you kind of have to get used to when wearing Birkenstocks but then feels very comfortable, at least in casual shoes. But I'm wondering if it might be a bad idea in hiking shoes, for long hiking days?
Also, they are very firm, not cushioned at all. Again, I like that around town, but maybe cushioning is more important for long hikes? #hiking #activity source