What are some alternatives?
When comparing FileApp and Documents by Readdle, you can also consider the following products
iFile - If you need a new file manager for your device, iFile might be the answer you seek.
GoodReader - With GoodReader on your iPhone, iPod Touch or iPad, you can read virtually anything, anywhere.
Filza File Manager - Explore files and folders with list view or grid view. View / edit files with powerful viewers.
Documents Pro 7 - The ultimate all-in-one mobile office suite for the iPhone and iPad with 8 premium apps in 1.
Quick View Plus - Quick View Plus enables software users to view virtually any file or email attachment needed instantly & print files in more than 300 different file formats.
Freefileviewer - Free viewer for PDF, DOC, DOCX, PHP, CFG, DAT etc. files