Just received my Natural Boots and wanted to share a couple of quick pictures and thoughts. This is definitely an amateur "review" so let me know if I missed anything or there are any specific questions.
My Brannock size is a true 13D so I ordered true-to-size a la Gustin's suggestion and the length is great. In the picture below, I'm also wearing an Allen Edmonds Dundee in 13D and the length on the two are identical. For further reference, I wear a 12D in RW Iron Rangers/Wolverine Rowans and I would not have been able to size down on Gustin's boot. The heel-to-ball measurement seems pretty spot on as well. Obvious in both feel and visually looking straight down, the last is fairly wide ("neutral and accessible" from Gustin's description). I'd be lying if I said it wasn't a bit surprised by how wide it was, but I guess I just forgot that I ordered a work boot. Once I reminded myself of that, the width is 100% fitting. It probably didn't help I went immediately from wearing more of a dress boot to a work boot. Evident in the second picture below is the low toebox profile which I do prefer to a more bulbous toe aesthetic.
The soles are reasonably stiff, but definitely seem like they will break in and wear well. The Chromexcel upper feels fantastic and appears to be tightly grained, so I'm not anticipating any deep/unattractive creasing. One thing I noticed only after trying the boot on is the calfskin layered insole. It was Gustin's description, but I guess it didn't register with me. For those familiar with Poron insoles, it feels somewhat similar, although I'm sure it will break in if it is just layers of calfskin. The insoles stop just short of the middle of my arch - an interesting feeling. Not particularly bad or particularly preferred, but just interesting. Definitely hoping as it breaks in its presence goes away. The 270 degree welt is great and has no loose or errant stitching.
Overall I'm pleased with them and would probably buy another pair! They were a long time coming, but I'm definitely looking forward to wearing them! Access to CXL leather and USA GYW boots at the $199 price point is pretty difficult to come by unless you go the seconds route for a couple of different manufacturers. These pose a pretty good value (as with almost all of Gustin's offerings). I'm excited to seeing how they break in and handle wear!
Appreciate the thoughts! As others have mentioned, I was a bit concerned ordering boots from Gustin with no feedback to work with. Can't wait to get my #8s!