I'm going on my 3rd season with my Lowa Sheephunters. I've worn them in alpine and mid elevations and they simply rock IMO.
The Lowa Sheephunters are stiff and I would not want them any stiffer but when one is coming off the mtn with a load that stiffness is well appreciated.
Boots like packs are a highly subjective matter, your mileage may vary.
MtnHtr