Redundancy is a key requirement for business continuity plans and generally used in conjunction with critical applications like VPNs and VoIP.
Having the dynamic DNS service within the system is generally thought to be better from a cost savings and overall control point of view.
The hosts is in the cluster will never send traffic to the switch using this MAC address with the cluster IPv4 address so one would need to create a static ARP entry on the router (layer 3) in the attached network.
As with NLB in unicast mode: incoming traffic towards the cluster will be flooded to all ports in the switch/VLAN and not all vendors support this setup.
For example, Dell PowerConnect multi-layer switches officially don't support MS NLB in multicast.
It works by creating multiple host records (usually A and/or AAAA) for one machine.
In addition to the before mentioned, to configure a terminal server cluster, one needs a load-balancing technology such as Network Load Balancing (NLB) or DNS round robin.
A load balancing solution will distribute client connections to each of the terminal servers.