Most of the bugs have been squashed, but it's still not a final release
WordPress 3.5 is almost here, for now, the second release candidate is available for testing. If you haven't given the upcoming WordPress 3.5 a try, this is one of your last chances.It goes without saying that you should test your themes and plugins as soon as possible, before the release is pushed to millions of people.
The one big new feature in WordPress 3.5 is the new Media Manager. It makes it easier to upload photos, audio and video and embed them into posts.
The new Media Manager is already live on WordPress.com, you can check it out there if you don't want to install a pre-release version of the CMS.
WordPress 3.5 is scheduled to land on December 5, assuming no show-stopping bugs are found in the meantime.
WordPress 3.5 Release Candidate 2 is available for download here.