RHEL 5.7 is a release that hasn’t a lot to be excited about, which, to be fair, is normal for an update of an enterprise Linux distribution. Koen Vervloesem sees what’s under the hood…
Pros: RHEL 5.7 is mostly about hardware compatibility and performance enhancements,as well as the new subscription service.
Cons: A number of interesting RHEL 6 features didn’t get backported, such as libguestfs, the SELinux sandbox and the kiosk mode.
Homepage: Red Hat
Although the newest Red Hat Enterprise Linux (RHEL) release is 6.1, Red Hat continues with updates for its previous 5.x release. The latest RHEL 5.7 gets some of the goodies of RHEL 6.x, in particular with respect to KVM: migrating KVM virtual machines is faster, CD drive emulation is enhanced and issues with the boot order of virtual machines have been fixed.
rest here