SpaceFM is a fork of PCManFM that was created to be more customizable than PCManFM.
Ranked in these QuestionsQuestion Ranking
Pro Incredibly customizable
Just right click on any menu or menu option (including the context menu itself) and you'll be allowed to customize it. This lets you add support or integration for features you find missing.
Pro Minimal dependencies
It only needss gtk, udev, desktop-file-util and shared-mime-info which is available in most systems.
Pro Desktop management support
Can be used to set wallpaper and desktop icons with high configuration support.
Pro Tab and panel support
SpaceFM supports up to 4 individually customizable panels as well as multi-tabbed file management.
Pro Easily open folder as root
Can open different folders as root, this way you don't have to use the terminal to move around files for which you need root permission.
Pro Highly extensible
Functionalities can be extended by user scripts as plugins. Some scripts can also be downloaded from https://github.com/IgnorantGuru/spacefm-plugins/wiki. Plugins can be exported too.
Pro Gtk-2 and 3 support
Available in gtk2 and gtk3
Con Some operations are slow
Because it tries to be as lightweight as possible and tries to use very little RAM. This can unfortunately lead to it being slow sometimes.