EBookDroid is a highly customizable document viewer for Android. Developed by Andrei Komarovskikh & Alexander Kasatkin
License: Free
MuPDF is a free and open-source software framework written in C that implements a PDF, XPS, and EPUB parsing and rendering engine. It is used primarily to render pages into bitmaps, but also provides support for other operations such as searching and listing the table of contents and hyperlinks. Developed by Artifex Software, Inc.
License: Open Source
EBookDroid is a highly customizable eBook reader with extensive format support and advanced features like annotations and text-to-speech, making it suitable for power users. In contrast, MuPDF is a lightweight, fast PDF viewer that excels in document rendering and simplicity, but lacks some of the advanced features found in EBookDroid.