Well, one thing I can tell you. Most people with a bad ankle carrying a pack in the backcountry are better served with a good boot than an elastic brace.
For most, the concern is rolling the ankle over to the outside. The way a brace goes on your foot, the angles that it applies tension, and the relative weakness of the elastic doesn't help much with that. If the elastic had enough tension to really help, you couldn't put it on and take it off. Taping is much better but for a multiple day trip it's a huge pain in the ass.
