The user interface geniuses decided to remove a button from Firefox 4 that was a critical tool for anyone who reads feeds- the feed icon on the right side of the address bar.
Luckily- there is a Firefox addon that puts it back:
Adds the old FF 3.X RSS Icon behavior back into FF 4.Specifically, when a page contains link tags in it’s header with a type of application/atom+xml or application/rss+xml it places the orange RSS icon into the right side of the location bar a.k.a. urlbar, awesomebar. If one and only one feed is detected, then clicking on the icon invokes your feed-handler see about:config browser.feeds.handler. If multiple feeds are detected, it popups up a little menu to allow you to select which feed to add.This addon DOES NOT look for links to rss/atom files in the body of a document.
Overall, Firefox 4 has been an adjustment- the moving of the tabs to the top is still a new behavior to learn. Manage bookmarks isn’t there anymore- you go to Show all bookmarks in order to edit your bookmarks and manage them.
The best part- is that Flash in one tab can’t crash the whole browser- like Google Chrome. I’m not feeling the promised speed from Firefox 4- but, I am much happier that the browser no longer crashes when bad code behaves badly.