I love that it has so many options to choose from with different protocols (ftp/smb) - also great for transferring large files between servers within my network! It's easy enought if you know how FTP works but not very intuitive in its UI; there are some things missing when compared to other clients like WinSCP or CyberDuck which have more advanced UIs.
We use crush ftpserver primarily as an SFTP client though we do occasionally need access via HTTP. The ability to easily move data over various protocols at once makes this software extremely handy especially during deployment of applications where one needs quick transfers without having to worry about port forwarding issues etc.