These are the recommended build tools for using the arcgis-js-api Bower installation. You can read more about Bower here.
You would use the Bower download of the ArcGIS API for JavaScript if you wanted to create local builds of your application. This is similar to what you can do with the JavaScript Optimizer but locally. This can also provide an improved debugging experience as you will know which module an error originates from.
If you want to build your application using Dojo, we recommend grunt-dojo and the included build.profile.
The bower release of the ArcGIS API for JavaScript is simply a minified version of the API.
The demo Dojo application can be found here;
You also have the option to use RequireJS as the AMD loader with the API instead of the Dojo loader. There are some limitations in this regard. The RequireJS loader is missing some methods that might be required at runtime, one of which is a cross-domain loader. You can view the provided Gruntfile for information on some build limitations. These mainly have to do with limitations in how the r.js optimizer performs builds.
The demo RequireJS application can be found here;
If you run into issues during the Bower installation process due to firewall settings, you may need to use the following command:
git config --global url."https://github.com".insteadOf git://github.com