Well done to the CentOS team who have, again, managed to build their new release (6.4) from Red Hat sources just two weeks or so after Red Hat published their new code. (RH6.4 was released February 21st; CentOS 6.4 was released last Saturday, 9th March. Impressive -and they beat Scientific Linux to the punch once more. Oracle Enterprise Linux 6.4 was out a week earlier still, of course, but I kind of expect Oracle Corporation to do that: they have significant resources to bring to bear on it, after all).
The release itself doesn’t have anything you might call significant in it, as the increment in merely the minor version number more-or-less tells you in advance.
Oracle 22.214.171.124 and 126.96.36.199 run on it fine, and a Kickstart file that does duty for auto-configuring a 6.3 server performs flawlessly for a 6.4 server, too.