I've purchased from three knives from Watanabe, all custom works. He was transparent about how long the knife would take before payment. He usually delivered one week before the promised time. He takes payment before production of customs.
I've purchased from other Japanese makers direct online such as Konosuke, Heiji, Hide, and Sakai Takayuki and Ikkanshi Tadatsuna back in old days. Shinichiro's response time was relatively good (about once a day in my experience). His English is good. He provided photos of knives upon request before shipping. He sometimes provides complimentary upgrades (I ordered customs with engraving and he gave a gem upgrade that cost on the website. read about another guy who got a free handle upgrade) but obviously this should not be taken as a guarantee.
Overall, knives arrived sharp but detail in F&F was frankly not great. None arrived with anything that could not be fixed with a little touch up but for the OCD-types, there may be some concerns. i.e. there were some light scratches on backsides of all the knives. The keyaki handles came in different shades (to be fair, it was actually in the photo but I wasn't paying close enough attention). Extra saya was not color matching the handle (custom fit type without pin)
My current thought about Watanabe: I want a Kintaro Ame real bad but my conscience prevents me from buying another Yanagiba given I have four and only do Sashimi once a quarter or so. Pricey, too.