Taken from the new BackTrack Site :

BackTrack 4 Final is out and along with this release come some exciting news, updates, and developments. BackTrack 4 has been a long and steady road, with the release of abeta last year, we decided to hold off on releasing BackTrack 4 Final until it was perfected in every way shape and form.

With this release includes a new kernel, a larger and expanded toolset repository, custom tools that you can only find on BackTrack, and more importantly, fixes to all (well, most..) major bugs that we knew of. This release we received an overwhelming support from the community and we are grateful to everyone that has contributed to the success of this release.

We’ve moved BackTrack to a dedicated home, where you will be able to keep updated with the development status and latest news. Our goal was to finally produce a focused and dedicated security Linux distribution that has its own resources, personnel, and drive that have dedication in making BackTrack better than it has ever been.

When you download BackTrack 4, we hope that you will agree, that this is the best release that has ever been accomplished from the BackTrack team – appropriately codenamed “pwnsauce”.