There's no uncertainty about this: The Fedora 20, "Heisenbug" beta release is here and is a fantastic sneak peek into the final Fedora 20 release. It's jam packed with fantastic free and open source software, lovingly configured and ready to use.
What is the Beta Release?
The beta release is the last important milestone before the release of Fedora 20. A Beta release is code-complete and bears a very strong resemblance to the third and final release. Only critical bug fixes will be pushed as updates up to the general release of Fedora 20. The final release of Fedora 20 is expected in early December.
Since it's a beta release, some problems may still be lurking. A list of problems that we already know about can be found at the Common F19 bugs page, found at http://fedoraproject.org/wiki/Common_F20_bugs.