While they have some similarity, they are not same.
MAAS focused on baremetal OS installs, DHCP, PXE, IPMI.. It has some VM management capability with KVM that is not its strength.
Harverster's focus is more on VM management. In that aspect it is more close to CloudStack or OpenStack with simpler interface and management. If Harvester handles a bit more of the baremetal stuff, I would be happy to move over from MAAS.