Hi Jamie,
Use fail-over, if both fail-over hosts have the same hostname, you save a CPS license. ;-) Then you can use really nice fail-over solutions from HP, IBM, or Oracle. I think even Microsoft has something to fall over ... sorry, silly pun.
The problem with active-active clusters is that you do not get the performance you would expect, so running two systems simultaneously means two licenses, which is costly and ineffective.
Regards,
HP