For backcountry skiing on big boards and in big terrain, you want a boot that's both stiff (for downhill performance) and flexible (for skinning up). That's a tall order, and most alpine-touring boots sacrifice stiffness for flex. Not the Zzeus (Gaia is the women's version). It manages both so well that our tester said, "It's the first boot I've used that's comfortable in tour mode and really performs like an alpine boot on the descent.
I used it for backcountry and frontcountry days." The secret recipe: It has polyurethane for lateral stiffness (like an alpine boot), softer material on the overlapping cuff for easy forward flex, and a four-buckle system locks everything down for maximum support on the descent. Bonus: Interchangeable soles (included) mate with any alpine or alpine-touring binding. All that, and it's not overweight. $689; 8 lbs. 3 oz. (m's 26 w/ AT sole); men's 25-30.5, women's 22.5-27.5; dynafit.us