Watch out our blogs for postings about the new features over the next weeks.
Best new feature for me personally?
The developer install mode. You don't have to go for big virtualbox anymore to test something quickly. Just execute the installable, make some choices and after 20 minutes ready you are.
Just start JDeveloper and the embedded Weblogic server in JDev. Everything is in here now. An in-memory database and fully functional soa and bpm domain. That's great! Never seen reacting JDev so fast and having that small deployment times. Absolutely great! Wait until you even see the new Debugger on composite level… :-)