TotalCommander
For me
TotalCommander is the best file manager. For a long time I am using two window file manager also on my regular PCs. Moving files around can't get any easier. It offers drag&drop, dealing with zip files, built-in text editor, bookmarks, yadayadayada .... TotalCommander also has a bunch of extensions to help with LAN connections, FTP, WebDAV and more. For instance, my ownCloud system is connected via WebDAV.
For me, TotalCommander is the one-stop solution for everything file related. Maybe some of you would like to give it a try.