I have a pair, because I wanted brown boots for schooling, and they were reasonably priced. I can’t speak to fuller calf fit, because mine are slims, nor to customization. The leather isn’t great, but frankly, isn’t any worse than the cheap Ariat line. This is the first pair of zip boots I’ve had, and I HATE the back zip; it’s held up, it’s just incredibly uncomfortable to me, and it doesn’t stay zipped up. My biggest issue is that the soles have worn almost through and are separating after less than a year of use, and I have one horse who gets ridden 4-5 days a week, so we’re not talking a ton of wear and tear.
That said, the boots have gotten a lot of compliments and broke in reasonably well. I haven’t been wearing them because I’m on the fence about whether it’s worth getting them resoled.