I used this for a bit ages ago. Useful tool. Funnily, I think it's a great example of how building some things is way harder than people think. For instance, everyone has complained about Calibre since the beginning of time. Code, UI, everything. And yet, no one has come up with a replacement. Maybe pandoc captures some use cases.
It's like OpenSSL in that respect alone. Everyone wants something like it but it's too hard to build so they'll just use what they think is an inferior solution (when really it's superiority as a solution is that it exists).
Another comment here exemplifies this by reminiscing how they worked up a design draft for their Calibre competitor yet never even started it because it's just too hard and unrewarding.
I also think people are too hard on the author's personality quirks. Yes, they can be grating, but this quirky person is presumably the sort of person who can build it and continue shepherding and maintaining it for over a decade. None of us with our infinite patience and epic social skillz apparently are doing it.
How many here have even maintained a popular, complex product for any real duration? Or had to be your own product's customer service agent? It's not easy. I've seen people break down just fielding customer demands at Target during one summer job.
It's like OpenSSL in that respect alone. Everyone wants something like it but it's too hard to build so they'll just use what they think is an inferior solution (when really it's superiority as a solution is that it exists).