At what point does an FTP client require a $40 price tag, or a $10 upgrade fee? WS_FTP and WS_FTP Pro aparently. its a FTP client for crying out loud! it transfers files from point a to point b, that is all it does. IPSWITCH's customers must be blind to pony up $10 just for an upgrade.
FileZilla, on the other hand, is free. it has a very nice UI, lets you save bookmarks to servers. what else does a FTP client need to do? your laundry?