When comparing Pantheon Files vs nnn, the Slant community recommends nnn for most people. In the question“What are the best file managers for UNIX-like systems?” nnn is ranked 1st while Pantheon Files is ranked 20th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Easy to use
Pantheon files (like the Pantheon IDE) is very stylish and minimal. It's minimal and very easy to use. The most useful commands are there in plain sight, on the toolbar or the sidebar.
Pro supports natural sorting of file names
Dolphin and Deepin File Manager support it, too.
Pro Superfast
Pro Rich set of plugins
Pro Extremely lightweight (120 kb)
Pro Unique navigate-as-you-type mode
Pro Awesome new features being added in every release
Pro Minimal configuration with sane defaults
Default options and navigation is simple to grasp.
Pro Has a great wiki
Pro Sessions
Save and resume sessions.
Pro Supports cd-on-quit
Allows for quick switching between nnn and the terminal.
Pro Previews
The file manager has recently added support for preview hovered files using various methods.
Pro Integrates with the desktop environment and opens files in the default applications
Pro Reasonably well-documented
However, it requires some prior knowledge of inner workings of Linux and there are no tutorials (yet). NNN author is making up for this by actively responding to GitHub issues.
Pro Customizable icons and colors
Cons
Con Buggy
Was missing basic network connect features when Loki launched.
Con Not very advanced
Pantheon files (like Elementary OS itself) does not offer many advanced features since it's mostly aimed at beginners.
Con Unstable software, not a file-manager
really, really dangerous stuff.
Crashes and take your work/files into the nowhere - aware.
Con Not intunitive
In some instances it is impossible to create a new folder. There just isn't right-click option or icon for it anywhere.