When comparing pico vs Cirrus, the Slant community recommends Cirrus for most people. In the question“What are the best minimal CSS frameworks?” Cirrus is ranked 9th while pico is ranked 27th. The most important reason people chose Cirrus is:
Supports both Flexbox and CSS grid making it a great modern choice for designing web apps.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Built-in cheat sheet for shortcuts
All command characters are shown at the bottom of the editor.
Pro Easy to use
Pico includes only the bare minimum of functionality needed to edit documents making it very simple.

Pro Supports Flexbox and CSS Grid
Supports both Flexbox and CSS grid making it a great modern choice for designing web apps.

Pro CSS Only
No additional JS/jQuery required to use.

Pro Mobile Responsive
Extremely responsive and supports many smaller screens.

Pro Open Source
Open source and quite actively maintained on Github.

Pro Lightweight
Much smaller than Bootstrap with just as much flexibility.
Cons
Con No way to override command characters
Characters such as ^D, ^T, ^L, etc will always be interpreted as commands and there's no way to write them in text.
Con Lacks some commonly expected functionality even for a basic editor
Pico lacks search and replace functionality as well as the ability to work work with multiple files at the same time.
