What are some alternatives?
When comparing FileApp and Filza File Manager, 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.
Touch Copy - TouchCopy - Copy Music, Messages, Photos, Notes and a lot more from your iPod, iPhone and iPad back to your Windows PC or Mac.
Documents by Readdle - A central hub for all your files.
iMazing - iMazing lets you transfer music, files, messages, apps and more from any iPhone, iPad, or iPod to a computer, Mac or PC. Manage and backup your iOS device simply without iTunes. (was DiskAid)
GoodReader - With GoodReader on your iPhone, iPod Touch or iPad, you can read virtually anything, anywhere.
Decipher Backup Repair - Fix corrupt and buggy iPhone backups so that you can restore your backup in iTunes!