When comparing Krunner vs Ulauncher, the Slant community recommends Ulauncher for most people. In the question“What are the best Linux app launchers?” Ulauncher is ranked 5th 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 Supports extensions in Python
Pro Able to launch Kdialog, Zenity and Bash scripts
Extensions are easily created. Python script is all open to see. Not compiled like some.
Pro Supports fuzzy search
You can enter app name with a typo and Ulauncher will still be able to find it.
ULauncher supports themes and comes with a good supply on install but more can also be made.