Here's what other sites are saying:
The Head Peak XP Alpine Ski Boot gives you the power to attack the whole mountain without feeling like your foot is in a vise. An EVA liner with custom HP Breathing Concept and a wide last (106mm) gives you the comfort to stay out all day. That doesn't mean that these boots don't perform. The Peak XP was built to go fast. The mid-stiff flex (90) gives you plenty of power control in the turns, even at Mach 9.