Gulp looks very interesting. Browserify vs. RequireJS seems more complex to me, though - it isn't difficult to use RequireJS in the CommonJS pattern. When I tried Browserify it was incredibly slow to build - but that might have been me setting it up wrong in Grunt...
I think the author oversimplified the choice of Browserify and RequireJS. They have some overlap, but are not 100% replacements. Both have the concept of modules, and they overlap in this area. Browserify allows you to use Node style modules in the browser. RequireJS allows you to asynchronously load parts of your app, while Browserify bundles all JS into a single file.
If you're planning on going that route with RequireJS, you should also look into AlmondJS: https://github.com/jrburke/almond