Agreed. It might not always be the most performant option, but it's reliable. I only use CDNs in dev environments, for quick tests, or for non-public facing min

Agreed. It might not always be the most performant option, but it's reliable. I only use CDNs in dev environments, for quick tests, or for non-public facing minor temporary projects. If they go permanent I switch to serving the libraries locally. More often than not when I am dealing with a CDN in these situations, it's from CDNjs alone -- if I can't get it from them, I take the extra few minutes to serve it. I'll either serve each library separately, bundled, or bundled with my own client code. at least until es6 modules are ubiquitous. In enterprise situations, it's a little different. I work for a company that pays Akamai a significant sum to make sure all of that's sorted out for anything large. Custom client code usually is served locally -- depending on the project.