I don't know of anything that is completely broken, but some functionality requiers chrome: On Google Docs, paste as markdown, copy and paste from menus, paste

I don't know of anything that is completely broken, but some functionality requiers chrome: On Google Docs, paste as markdown, copy and paste from menus, paste without formatting, etc. only works on chrome. This functionality could be done with standard APIs, but instead google uses a hidden, pre-installed extension to implement it. Offline mode doesn't work on firefox for either gmail or google docs. Google doodles don't show up on Firefox Mobile, unless you spoof a chrome user agent. Youtube has repeatedly had serious performance problems on Firefox.