When comparing Pleeease vs Stylecow, the Slant community recommends Stylecow for most people. In the question“What are the best CSS preprocessors/postprocessors?” Stylecow is ranked 7th while Pleeease is ranked 12th. The most important reason people chose Stylecow is:
It's written in node, so you can install it with npm. All available plugins are installed by default and include some development tools like a watcher and a browser live-reload so it don't need more than few seconds to be ready to start to work.
Ranked in these QuestionsQuestion Ranking
Pros
Pro All-in-one post processor
preprocess CSS (experimental)
adds prefixes, based on Autoprefixer
provides fallbacks for rem unit, CSS3 pseudo-elements notation
adds opacity filter for IE8
converts CSS shorthand filters to SVG equivalent
packs same media-query in one @media rule
inlines @import styles
minifies the result
generates sourcemaps from pre- to postprocessors
Pro Combines media queries into single rules
If you have repeated media queries in your stylesheet, Pleeease will pack them into a single media query when compiled.
Pro Rem fallback
Rem unites are not supported in IE8 and below, so Pleeease provides a pixel fallback.
Pro Uses Autoprefixer
Pleeease uses Autoprefixer to add vendor prefixes based on which browsers you want to support (prefixes are added based on information from caniuse.com.
Pro Easy to install and use
It's written in node, so you can install it with npm. All available plugins are installed by default and include some development tools like a watcher and a browser live-reload so it don't need more than few seconds to be ready to start to work.
Pro Advanced API and parser
The parser detects any CSS syntax error found. The output code can be customized to follow your own code style rules (indentation, spaces, string quotes, etc). It has a clean and powerfull API, which make easy to create new plugins.
Pro No need to learn a new syntax
Since Stylecow allows developers to write simple, vanilla CSS, there's no need to learn a whole new language.
Cons
Con Not very popular
Pleeease is not very popular. This may make finding guides, tutorials or resources outside the official ones difficult.
Con May be merged with PostCSS in the future
Since Stylecow is pretty small and hasn't gained a lot of traction in the past 5 or so years since it was first released but also because it serves kind of the same purpose as PostCSS which is much more popular, there have been discussions on merging the two projects together.
Con Small community
Stylecow doesn't have a very large community. This can make it difficult to find answers and increases the risk of the project being abandoned.