The DSS V7 guides you during your configuring the Failover so this reduces incorrect configurations - very simple.
The processing power on both cluster nodes means that the load balance is provided.
Consider if the traffic in your city grows to a point where you have to build 2 lanes for the roads instead of one lane only to speed up the flow.
Increased sensibility for network Failures, if in the even there is NIC issues on one of the nodes then the cluster will make the switch to the one that is able to see the network for the ping nodes and auxilary ports. This is important especially if a cluster is to communicate over the network.