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.
Con Cannot use any npm module
Since SystemJS does not try to shim node built-ins and methods from modules, you cannot load any npm module in the browser and expect it to work with SystemJS.