There is one brand new tool, virt-log. And I rewrote the virt-v2v and virt-p2v tools. These tools convert VMware and Xen guests and physical machines, to run on KVM. They are now much faster and better than before.
As well as that there are hundreds of other improvements and bug fixes. For a full list, see the release notes.
Libguestfs 1.28 will be available shortly in Fedora 21, Debian/experimental, RHEL and CentOS 7, and elsewhere.