mountainscapegoatwrote a review of Mammut Taiss Light Mid GTX Mountaineering Boot - Men's on August 14, 2019
Familiarity: I've used it several times
Fit: Runs small
Just took these for a 20 mile spin with a 50lb pack. First impression was good. Very light, great support for the weight, and great build quality.
The initial few wears around the house left me with the impression that fit was pretty true to size, but BE WARNED! What I couldn't tell until I got some miles on them was that the narrow, almost pointed toe box caused the boot to put a good deal of pressure on my smallest toes on any kind of sustained down hill. I would advise folks with average width feet to consider sizing a half size up, and those with wide feet going a whole size up or to look elsewhere.
I'm getting a half size larger pair on the way ASAP and will update my review when I get some miles on those.