The file list window is basically a more compact version of the file browser window. It displays only one listbox, which results in the fact that the contents of opened directories are always displayed in the same listbox, and it doesn't have a status bar. Its advantage is that it is more quickly created than a file browser window and occupies less space on your screen. My usual setup is that I have one file browser and lots of file lists opened.
The menu bar of the file list windows is also more compact, but allows access to all menus of the file browser through submenus of the "Others" menu. This menu contains one additional entry to open a file browser window displaying this file list's directory.