Related to the antivirus itself, it now has another interface which is optimized especially for unexperienced users. It includes "Search Advisor", which automatically warns you if you visit a website reported as infected (all links are automatically checked with BitDefender's servers), a new utility which displays you all applications that are stressing your computer and suggests you ways of fixing them, and a new mechanism, which assures the optimum speed of the computer (the antivirus adapts its use of resources dynamically, depending on the available resources of your computer).
The detection rate has been improved compared to the earlier version (with the help of new methods of detection and upgraded existing ones), and I can really say that this places BitDefender on top of the world's most powerful antivirus suites. However, as usual, BitDefender has important problems related to the fix of advanced and complex malware. This kind of problem can even make your system unable to boot.... so this is an important thing that is not yet resolved.
If you want, you can download and test this security suite, but as it is a Beta 1 version, I don't recommend you using it in an environment in which the security is something essential.