I set out for Colorado for a fourteener winter ascent…
Materials: Leather, vibram, gore-tex
Break-in Period: Moderate
Price Paid: $270
I set out for Colorado for a fourteener winter ascent and instead of the usual crusty snow we encountered the biggest snow storm to hit the front range this year (Feb 2010) which made mountain conditions an all out winter mountaineering experience.
My feet stayed warm but I did not sweat much in them at all; overall excellent insulation. The temperature was about -10 F with a wind chill into the negative teens/low twenties. The first part of our ascent was normal hiking on snow without snowshoes and they did not give any problems; they were extremely comfortable for a mountaineering boot, however, don't expect them to fit like street shoes.
I sized up a half size from what I normally wear and that worked great for me. I did not develop any blisters or hot spots in our 18 mile hike. They fit very similar to Lowa's hiking boots. I did wear them for 25 hours at work and went on one 3 miles hike in the snow before I took them out and that was enough break in time.
They went great with snowshoes and especially great with crampons. I didn't even use automatic step-in crampons but I can only imagine the improvement because of how good they performed with strap-on crampons. The sole is extremely stiff which is what you want for a mountaineering boot. If you were to venture into colder temperatures a super gaiter (over boot) would add the extra warmth for any expedition.
From someone who has actually used them in harsh mountain conditions I highly recommend this boot.