When comparing XtraFinder vs nnn, the Slant community recommends nnn for most people. In the question“What are the best Mac file managers?” nnn is ranked 5th while XtraFinder is ranked 10th.
Ranked in these QuestionsQuestion Ranking
Pro Old full-size color labels from OS X < 10.9
Pro Adds useful toolbar items
XtraFinder provides useful options for toolbar such as: Launch as Root, New Terminal Here, New File..., and Select...
Pro Additional right-click options
Xtra Finder provides additional options when performing the right click.
Pro Custom hotkeys
Pro Copy Path
Pro Can open a terminal in set position
XtraFinder can open up a terminal from the right-click menu in given path with "New Terminal Here".
Pro Dual panel
Split the Finder window into to windows to achieve better file handling.
Pro Colored icons in the Finder sidebar
Pro Extremely lightweight (55 kb)
Pro Rich set of plugins
Pro Has a great wiki
Pro Minimal configuration with sane defaults
Default options and navigation is simple to grasp.
Pro Unique navigate-as-you-type mode
Pro Awesome new features being added in every release
Save and resume sessions.
Pro Integrates with the desktop environment and opens files in the default applications
Pro Supports cd-on-quit
Allows for quick switching between nnn and the terminal.
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.
The file manager has recently added support for preview hovered files using various methods.
Con Doesn't work on recent macOS versions without a workaround
This tool doesn't work on recent macOS versions, except if you try workaraound that may or may not work. It involves disabling System Integrity Protection and details on how to do it can be found on the XtraFinder website.