Based on our record, MuPDF seems to be more popular. It has been mentiond 21 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Sioyek uses the MuPDF engine, which supports EPUB: https://mupdf.com/. - Source: Hacker News / 10 months ago
MuPDF mini (version 1.23.3a): Minimalist viewer for PDF, XPS, CBZ, unprotected EPUB, and FB2 documents. Source: over 1 year ago
Mupdf is the mupdf of epub; it supports epub and other formats beyond pdf¹. When I've had really large files I've used mupdf to read them a few times, as it seems to be far better at handling them than other tools. ¹ https://mupdf.com/. - Source: Hacker News / over 1 year ago
Doesn't exactly fit your requirements, but might as well mention it here: muPDF - the most lightweight PDF viewer that I've ever seen. You don't even have to install it. Mobile version exists by the way. Source: about 2 years ago
MuPDF viewer (version 1.21.0a): Lightweight document viewer. Source: about 2 years ago
Sumatra PDF - Sumatra PDF is a slim PDF/DjVu/EPUB/XPS/CHM/CBR/CBZ/MOBI viewer for Windows.
Haihaisoft PDF Reader - Haihaisoft PDF Reader is the name of a free to use PDF reader and printer that is extremely simple to launch.
Foxit Reader - Foxit Reader is a free and light-weight multi-platform PDF document viewer.
eXPert PDF Reader - eXPert PDF Reader is a free to use PDF reader and views for the Windows operating systems.
Okular - Okular is a universal document viewer based developed by KDE.
Cool PDF Reader - Just like its name Cool PDF Reader, this small PDF reader is a really a cool PDF reader for viewing, reading and editing PDF files for free.