It took three tries to get the pair of boots I have on my feet.
The first try was mostly my fault; I had to do an exchange because the width didn't fit. DO NOT USE the fit guide in the boot ordering section—it only tells you to go down a size in length and says nothing about width. DO USE the "Easy Sizing Guide" found in the support area of the website. It covers both length and width, and it works perfectly!
On the second pair, the size and fit were perfect! However, I had to do a warranty exchange because the leather insole was over-trimmed by the ball of my foot, leaving just enough of a gap between the insole and the heel counter to cause some pretty bad pinching. Props to the warranty and exchange team—they were super friendly and made everything quick and easy!
On my third and final pair, the boots are absolutely amazing! The craftsmanship is top-notch. I’ve been wearing them nonstop for 28 days now. The insoles took about three weeks to break in, but the uppers took no time at all. The leather is so soft that I almost hope it isn't too soft to be durable, but only time will tell.
My only "concern" is that on this pair, the leather insole has even bigger gaps—this time between the insole and the vamp area. Because of the location, it isn't causing pinching for now.
All in all, I am super happy with my experience with JK. The boots look and feel amazing, and I'm excited to buy another pair!
Pictures are of before oil, after oil, and the gap.