I think it would be far more reliable to simply have two independent DHCP servers with mutually exclusive address ranges, and have one system be secondary and "delay" its responses by 2s so it always "loses" when the primary is up and running well.
Yes, you lose the ability for clients to get the same IP during a lease refresh if the primary is down, but that is a small price to pay for simplicity and robustness.
That depends on your scenario. In some situations it is important to get the same IP. In other situations, using potentially double the address space is unacceptable. If these points are not a problem for you, I certainly agree that two independent servers are potentially more reliable than a clustered setup. Steinar Haug, Nethelp consulting, sthaug@nethelp.no