When comparing Skeleton vs MUI CSS, the Slant community recommends Skeleton for most people. In the question“What are the best lightweight responsive CSS frameworks?” Skeleton is ranked 1st while MUI CSS is ranked 3rd.
Ranked in these QuestionsQuestion Ranking
Pro Responsive grid
Pro Style agnostic
Pro Vanilla CSS
No bells and whistles for Skeleton, it's just CSS.
Pro Media queries
Pro No external dependencies
11KB minified and gzipped
Pro Grid system - the same as Bootstrap
Pro WebComponents library
Pro HTML Email library
Pro React library
Pro Customizable using SASS
The MUI CSS can be easily customized by using the SASS files available on GitHub and via Bower. Customize breakpoints, font-settings and use Material Design colors.
Simple animations without too much fanciness keep the performance high and size small.
Con Not maintained anymore
No active development for two years.