I have worn these boots almost exclusively since I bought them in February, so I feel qualified to review them.

I needed comfortable, sturdy, stylish knee-high boots, and thought this an impossible dream.  I found many boots which are sturdy and stylish, but so flat or narrow in the toe box as to be utterly unsuitable.  I need my shoes to be foot-shaped.

After many hours of research, I found Keen's Bern Baby Bern and thought I had found perfection.  Lo, I was right.  These were comfortable right out of the box.  My toes had wiggle room, and the inner sole was firm but soft--so comfortable that I actually said it felt like walking on clouds.  I rarely get so silly about a pair of shoes.

Weeks later, my opinion of these boots has done nothing but improve.  The break-in period was very light.  I felt like the boots were a bit tight when I wore thick wool socks, but it only took about a week for this to stop.  The leather stretched and formed nicely to my shape.  There is an elasticized fabric panel under the two straps on the outside of each boot, which obviously enables the shaft to stretch over large calves, but I feel these boots would fit my athletic calves even without extra stretch.  Since constant wear has caused the boots to form so well to my feet and legs, I may eventually have a cobbler remove the stretchy panels and insert leather instead.

The outer sole is very sturdy, taking all the scuffs and bumps that might otherwise affect the leather toes.  I do have one small nick in the toe of the right boot, but it is practically invisible unless you are peering right at my feet, which would be weird.

The short heel is no worse than the heel on my Corcoran Jump Boots; I never feel the extra height has an adverse effect on my legs or back.  I can walk all day in these Keens, on concrete and on hard floors, and experience no pain or discomfort.  I do not feel at all inclined to kick these off when I finally get home.

The aforementioned buckled straps and stretchy fabric panels, along with the height of the rubber "bumper" that is the outer sole, give this boot a decidedly casual style.  They look good with skirts and are definitely on the nicer end of casual, but I feel the features that make this boot so rugged and comfortable might be too clunky for a more elegant style.  They remain quite elegant for what they are, though, and you really can't do better for a leather boot if you walk everywhere, but still want to look nice.

For reference, I am 5 feet, five inches tall, 130 pounds, with strong calves measuring just over 15 inches.  After much wear, I feel the boot shaft could stand to be a very little bit tighter, especially in the ankle area, but they have held their shape remarkably well considering how much walking I do.

TL;DR: Extremely comfortable, fashionable, high-quality leather boot for walking and looking good doing it.  Great for all but the most elegant attire.  Stretch well to accommodate body shape, even on athletic legs.