Ranked in these QuestionsQuestion Ranking
Pro Registry agnostic
JSPM is registry agnostic, it can pull packages from npm and github and is built in such a way it can support more.
Pro Switch between async or sync load
With a simple command you could change between load the modules async by systemjs or sync with a bundle file.
Pro Module style agnostic
Loads ES6, AMD, CommonJS and globals.
Pro Can transcompile ES6, JSX and Typescript
Pro Versioned package urls
It creates a packages folders which are versioned. This makes it future proof for a time where we stop bundling all the code. In the following presentation Guy Bedford calls bundling an anti-pattern.
Pro Bundled based on imported modules without any config
Create the bundle file without config and add only the modules imported.
Pro Much faster than Webpack or Browserify
While Webpack and Browserify recompile the source code using Babel, jspm is the only packager that can load prebuild/minified code downloaded from the npm registry.
Pro Easy install packages from npm, github or any git repository
Pro Very easy to start with
Con Poor bundler performance
Bundling performance is slow, though offset by the fact that bundling is not required during development, since it can load dependencies asynchronously.
Con You need to be an expert to write shims
You can load any module. But that comes with the price:
you need to find or write configs to load a particular rare module.
Con Watcher has bugs
Watching would benefit from improvements
Con Unstable API
0.17 is still in beta. 0.16 is lacking features.
Con Doesn't hide complexity
JSPM doesn't try to hide complexity from the user. I.e. when some issue emerges you need understand a lot to be able to patch it or create a workaround.