14 DAY TRIAL // It's nothing official, but Mozilla is definitely ready to move to Firefox 9 as they uploaded a candidate for the stable release of this version. You can download it straight from their FTP server.
Officially still in beta channel, Firefox 9 is scheduled to become stable on December 20, when the code migration for all editions is executed.
Among the new features of this version is Type Inference for the JavaScript engine, which should basically bring a huge speed improvement. The speed bump recorded in benchmarks show a 30% faster Firefox in Kraken and V8.
Another important feature is support for querying Do Not Track status via JavaScript. DNT puts the users in control of the way information is collected by the websites they visit. The feature basically informs a page that you do not want your surfing behavior to be recorded by third-party content.
A more detailed list of new features is here. The current Firefox 9 build is still not a final product and may not be ready for official release.