Ranked in these QuestionsQuestion Ranking
Pro Supports multiple module formats
SystemJS supports AMD, CommonJS and ES6 modules.
Pro Can load static assets through plugins
System.js supports loading static assets such as images or stylesheets through loader plugins.
Pro No tools needed in dev, can seamlessly bundle when moving to prod
Pro Concise, Granular Configuration
Pro Easy to migrate to
A migration from RequireJS + loadCSS to only SystemJS can be done in only 2.5 hours.
Pro Even its dev. build is smaller than most of its competitors prod. build
With ~15Kb, its development build can load almost any type of JS module.