It's hard to speak to comfort as I feel that fit is a very personal thing. However, in terms of build quality I would say KW is in the upper tier. The fiddleback waists are a work of art. I had a GG Wigmore for a little bit and the soles of KW shoes are very comparable. By and large the best you can get. Carmina, C&J, Meermin, etc none of the shoes around the same price range have soles that are even comparable. Even my EG shoes don't have fiddleback waists. I think you'd have to either buy GG, EG Top Drawer, or AS handgrade to get it for over twice the price. Granted it's still GY welted and not hand welted but I doubt that really matters in the grand scheme of things. Other than that, the shoe has held up very well and the quality control is superb as are most shoes in this price range. The stitching and the welt are much better and more elegant than my AE shoes.
In terms of comfort, my KW shoes are probably half a size too big. I sized down by half on my loafers and that fits perfectly and is very comfortable. However, for my brogues, I think the instep is slightly higher and the aggressive waist may not suit my low arches as well my AE shoes in the same size. It's just slightly more uncomfortable from time to time. It's hard for me to give comparisons to my EG and Carminas as those are both half a size smaller as well. Personally, I think one of the best parts of buying from KW is the accessibility and free returns. You can try on the shoes and ship them back for around $30 total if you live in the US. A lot cheaper than buying and reselling shoes that don't fit from some of the less accessible brands.