QtFM is described as 'Lightweight file manager using Qt' and is an app in the File Management category. There are more than 25 alternatives to QtFM for a variety of platforms, including Linux, Mac, Windows, Xfce and MacPorts. The best alternative is Double Commander, which is both free and Open Source. Other great apps like QtFM are Midnight Commander (Free, Open Source), Dolphin File Manager (Free, Open Source), Files (Free, Open Source) and Thunar (Free, Open Source).
Dolphin is a file manager for KDE focusing on usability. Has three view modes: Icon, Detail and it used to have Column View like in Finder (it is not available in current version due to problems with maintaibility). Supports FTP, SCP and other protocols. Highly configurable.
Thunar is a new modern file manager for the Xfce Desktop Environment. Thunar has been designed from the ground up to be fast and easy-to-use. Its user interface is clean and intuitive, and does not include any confusing or useless options.
The Finder is the first thing that you see when your Mac finishes starting up. It opens automatically and stays open as you use other apps. It includes the Finder menu bar at the top of the screen and the desktop below that.