Mozilla was expected to include several brand new features like an in-built PDF reader long ago, but it seems like they never made it. We need to wait for future versions.
I've been following the Beta channel for a really long time, and I felt like practically nothing was coming at all. Firefox 5 has no UI refresh and almost no new features that will be noticed by most end-users. This new release supports CSS animations and more behind-the-scenes features and updates. Firefox for Android got a Do Not Track feature as well.
A feature that you will probably notice in Firefox 5 is that when you have a lot of tabs open and you want to close them, you will not need to jump here and there with your mouse. When tabs are small, they remain small if you're on a tab-closing spree, just like in Google Chrome.
Firefox 5 is now available for Windows, Mac and Linux. You can either download the browser from the Mozilla website, or you can click the Firefox button, go to Help, About Firefox and it will check for updates automatically (I think you need to click a button in that window on a Mac).
[via The Mozilla Blog]
