The Lowa Weisshorn GTX is a great all-around alpine or mountaineering boot that performs well on both steep glaciers and more mixed terrain.

Fit
The Weisshorn’s thick, split leather and Cordura upper features microfiber cutouts at the ankle to provide added mobility at a key pivot point, while the deeper than average Achilles notch adds extra flexibility. A webbing ankle lace loop comfortably cams your foot into place without restricting ankle motion when you need a bit more precision. The three-zone lacing system offers individualized comfort adjustments, while the roomy toe box ensures no black toenails at the end of the season.

Weight
A Split grain versus full leather uppers saves weight but might cut down on durability. A carbon inlay in the outsole reduces boot weight even more, while providing extra rigidity for automatic crampons.

Comfort
I found the Flexifit-Synchro system let my ankle flex in the boot, to the point where I was able to get flat footing (and therefore all crampon points engaged) on steeper terrain–great for glacier climbing. A full-length layer of PU (polyurethane) spans the midsole with an embedded carbon inlay. This inlay gives the boot tons of flex under the ball of your foot for walking, but ensures torsional rigidity for climbing. The Vibram Dolent rubber outsole offers great traction on slippery surfaces.

Warmth
The Gore-tex liner and Duratherm insulation keep your feet warm and dry. These climbing boots withstood below zero temps in Montana, Wyoming, and the Canadian Rockies. 

Precision
For steep glaciated terrain where full crampon contact is a safety must, the Weisshorn deliver. Clambering up rocky alpine ridges in the boots is not a problem either, with the ability to toe point and edge on more sketchy terrain. The sole is rigid enough to support automatic crampons. I had problems with that lack of overall stiffness for steep (WI 4-5+) terrain, as the boots made for sloppy feet and major calf burner sessions after climbing all day.