Stiff plastic and a double-injected cuff afford alpine-boot-like downhill performance, but thanks to a walk mode it feels like an alpine-touring boot on the way up. 8.3 lbs; garmontusa.com
Bonus: Further evidence of its split personality: It comes with two interchangeable soles, one a grippier ski-mountaineering sole and one a flatter, traditional alpine sole.
Bummer: All that performance adds up—they're heavy.