I have always owned and used Koflach boots since the 1980's. I know that there are a lot of new leather boots coming out now that are a bit lighter, and said to be perhaps a tad less stiff - and they probably ARE. But, I didn't find the weight between the leather boots and these all that much different per se, I looked at the LaSportiva's at a store and they seemed about as stiff to me, and - at a $510 price tag, I opted to go with the Koflach's instead. Great fit, super warm - and there is no way I am going to have to worry about getting wet feet - ever! I like them alot! These have been proven on extreme mountains such a Everest, K2, etc.
I used these boots for a climb of Mt Lafayette in NH on December 27, 2012 (the day of winter storm Euclid). We climbed on through extremely high winds, deep snow drifts, and practically zero visibility above tree line. This is my first experience with plastic boots and I was very pleased that my feet were warm the whole time despite deep snow drifts and a cold windchill. They performed exceptionally well with Black Diamond Contact crampons. I normally wear a 9.5 shoe/ boot and I bought a 10 which fits fine with one heavy wool sock. I plan to use these for a Mt Washington winter hike and Mt Rainier.
"Best Double Plastic Boot on the market!"
These the third pair of double plastic boots I've used and they are by far the best. The other being the Scarpa Inverno and the Koflach Degre.The liners are removable, so they're easy to dry, even if you just sleep with them in your sleeping bag overnight. The outer shell of the boot so very sturdy, with just enough ankle flex so that walking up sleep slopes isn't uncomfortable.Buy them and never suffer cold feet again.