While Mike Beltzner, Director of Firefox says that they are going to ship this version as their final, their site's main page still links to the download of version 3.6.
It doesn't appear, from the release notes that they have made a lot of changes and repairs since the previous beta. However, there are, as usual, loads of small fixes. But I noticed that there is a slight aesthetic change in the interface. The tabs are wee bit taller and more boxy. Also, there is a bigger distance between the Firefox button and the navigation bar.
Again, the next edition of Firefox onwards, the release cycle will be faster and new features will come quicker your way. Firefox 5, which should release in a few months is said to have site-specific features.
Download the Firefox 4 RC right here.