When comparing Krunner vs Rofi, the Slant community recommends Rofi for most people. In the question“What are the best Linux app launchers?” Rofi is ranked 1st while Krunner is ranked 9th.
Ranked in these QuestionsQuestion Ranking
Pro Extensible with plugins
Krunner can be extended with the use of "runners" which are essentially plugins for the app launcher to allow for extra functions.
As it is written in Qt QtQuick using QML.
Pro Can be used to open websites
By just typing an URL into the text box users can have the site open in their default launcher.
Pro Can run commands
<code>run: st toxic</code> Runs a tox client in the terminal emulator "st".
<code>run: maim ~/Images/screenshots</code> take a screenshot with "maim" and save it to given location.
Pro Minimalist design, yet can use customizable themes
Also it's easy to make use of your own "plugin" (scripts).
Pro Great keybindings
They seem to be emacs based.
Pro Case insensitive
Instead of having to worry about case sensitive characters, you can use caps or lowercase wherever you please without causing any issues.
Pro Clipboard history extension
Greenclip adds clipboard manager functionality: https://github.com/erebe/greenclip
Pro Easily switch windows without mouse
Con Issues when Caps Lock is active
When typing with Caps Lock activated, it's impossible to use Backspace. Rofi eventually freezes in this scenario.