Gold standard? What the hell are you smoking? The software is absolute garbage. The reader is slow and conversion is broken. I have tried every version for years and it never improves. It can't even convert tabular data properly.
Convert the PDF of "Dive Into Python 3" by Mark Pilgrim into ePub and look at the resulting mess. First page:
"AreyoualreadyaPythonprogrammer?Didyoureadtheoriginal“DiveIntoPython”?Didyoubuyit on paper?
What happened to the spaces? You will find numbers throughout pages, often in the middle of a page, which are the page numbers from the PDF.
I made a searchable PDF of my W-2 using Abby Fine Reader and tried to convert that to ePub. The end result is a blank page. I created tabular text of my computers: CPU, and GPU, and memory. I saved as PDF and converted it to ePub; the table is gone with one entry per line.
Dog shit has more value than this garbage.