In my career I used requirejs, browserify and webpack. I currently find webpack the best. Contrary to many opinions its very easy to configure (along with Babel and JSX preprocessors). And it's much faster than browserify (IMHO). Webpack also comes with a lot of features out of the box (like concatenating, minyfying and producing source maps) without the need to add separate packages. Webpack is currently my number one choice. Browserify is good. Requirejs is something I'd rather not go back to.