What are some alternatives?
When comparing Offline Explorer and FileZilla, you can also consider the following products
HTTrack - HTTrack is a free (GPL, libre/free software) and easy-to-use offline browser utility.
Cyberduck - A libre FTP, SFTP, WebDAV, S3, Backblaze B2, Azure & OpenStack Swift browser.
WebCopy - Cyotek WebCopy is a free tool for copying full or partial websites locally onto your harddisk for offline viewing.
Beyond Compare - Beyond Compare allows you to compare files and folders.
Wget - GNU Wget is a free software package for retrieving files using HTTP(S) and FTP, the most...
PuTTY - Popular free terminal application. Mostly used as an SSH client.