I've been thinking of working towards an RHSA but the news of RHEL7 and all of the major improvements gave me reason to pause. To me, this release is much more exciting than the RHEL5 ro RHEL6 release.
RHEL6 was awesome for the tickless kernel, and RHEL5 was rather long in the tooth at that time. The tickless kernel matters more in virtualization then on bare metal, and I virtualize a lot of stuff.
Does XFS do any kind of block-level checksums like ZFS or BTRFS?
No. XFS is an old school filesystem, as much as that can be said about a journaled file system.