When comparing Sly vs Pleeease, the Slant community recommends Sly for most people. In the question“What are the best CSS preprocessors/postprocessors?” Sly is ranked 8th while Pleeease is ranked 12th. The most important reason people chose Sly is:
By using whitespaces and nesting, you don't need braces or semicolons. This helps with keeping the syntax as readable and minimal as possible.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Readable syntax
By using whitespaces and nesting, you don't need braces or semicolons. This helps with keeping the syntax as readable and minimal as possible.
Pro Supports variables out of the box
Sly has out of the box support for variables.
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.
Cons
Con Extremely limited adoption
Sly has just 5 stars on Github and a very small adoption rate. For an open source project this usually means less bugs reported, lesser documentation and few third-party learning resources.
Con Not stable
Sly is in the alpha stage.
Con Not very popular
Pleeease is not very popular. This may make finding guides, tutorials or resources outside the official ones difficult.