When comparing Polo vs Krusader, the Slant community recommends Krusader for most people. In the question“What are the best file managers for UNIX-like systems?” Krusader is ranked 9th while Polo is ranked 15th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Purposeful layout choices
Polo wants people to get the file manager they want, but it's not awash with granular layout options that take ages to understand. First select whether you want one, two, or four panes, and then select a format for each pane of either List, Icon, Tiled, or Media. That's it, you're done.
Pro Installs smoothly on Debian, Redhat and Arch based distributions
File managers in Linux have a nasty propensity for being closely tied to the distribution family from which they arose. Using Polo allows you to have an identical file management experience when shifting between machines from different branches of the Linux tree.
Pro Device management
Quickly mount and unmount devices from the sidebar, including support for locking and unlocking LUKS encrypted devices.
Pro Youtube-dl integration
Just paste a YouTube URL into a folder and Polo will download the best quality format of it and save it in that folder.
Pro Archive browsing and creation
Browse archive files as those they were just another folder, dragging and dropping files in and out of them at will while the backend uses the appropriate tools to manage the archive file itself. Archive creation includes a rich assortment of controls over compression formats and structure.
Pro Image file actions
Rotate, resize, optimize, convert formats, save for the web and many other handy features all right in the context menu.
Pro ISO file tools
Mount ISO files to loop devices with just two clicks, or spin them up as a QEMU KVM instance, and for portability there's also an option to write them to USB flash drives using a GUI dialog.
Pro Advanced PDF file controls
Perform Merge and Split operations on PDF files without needing another file handler all from the context menu. Rotate and Password Protection settings are also expressed there.
Pro Cloud storage support
Includes its own rclone macros for adding cloud storage access to the list of browsable locations that just works, a welcome relief in the sea of hacks which provide those features elsewhere in Linux. Currently supported: Dropbox, Google Drive, Microsoft OneDrive, Amazon Cloud Drive / Amazon S3, Openstack Swift (Rackspace Cloud Files, Memset Memstore, OVH), Hubic, Backblaze B2, Yandex Disk
Pro Views
Supports up to four panes, plus a tree-style side panel and tabs.
Pro Terminal emulation
Built-in terminal pop-up.
Pro Launchpad PPA available
Debian-based distributions can leverage the apt package management system to keep Polo updated by adding the approved PPA to their apt sources, simplifying installation as well.
Pro Permissions management
Features a file properties side panel to easily assess and modify permissions.
Pro Great two-pane interface
Pro Folder synchronization
Pro Handles most archives. There is little difference in behaviour between an archive file and a regular folder.
Pro Virtual file systems
Search results as example saved into virtual folder and can be accessed later. All file operations may be performed on items in search results as if they were files in single folder.
Pro All common operations can be done with keyboard efficiently
In addition, shortcuts can be easily renamed.
Unlike Dolphin and many others.
Pro SFTP support
Pro Many operations like copying and moving files can be queued
Long running operations can be queued.
There is no point in doing them in a parallel way, as speed decreases dramatically.
Pro Can view and edit many files
Even editing a file inside a .zip file.
Has hexadecimal viewer embedded for binary files.
Pro Filename association and instant console availability
Pro Multi-rename tool
Pro Searching capabilities and copying/deleting/moving in background
Pro Custom commands can be added to the menu easily
And they can use the current folder, the selected files....
Cons
Con Freemium model
Many of the best features mentioned as pros are only available after a one-time donation of USD$10 or more. Until then you just have a fast, good-looking and otherwise forgettable file manager.
Con No drag and drop
You can't drag from one view to another.
Con Load loop
Slow opening with annoying 'load loop' dialog.
Con Lengthy beta cycle
Polo has been in the beta stage of development for longer than hoped for, and while mostly stable, isn't yet ready to be promoted as a rock-solid replacement for file managers such as Dolphin and Nautilus.
Con KDE dependencies
If you don't use KDE, you'll be forced to install quite a large amount of KDE libraries.
Con New releases are infrequent
It can be seen in https://quickgit.kde.org/?p=krusader.git that maintenance work is done in a continous fashion, but no new releases are provided.
Even though it is perhaps the more feature-rich file manager.