LTM Active/Active vs Active/Standby?

Prior to traffic groups, setting up an active/active HA pair was a little daunting. All of the VIPs/configs were identical on both boxes but some were disabled on each peer. You needed a failover event and mechanisms to both 1) enable the disabled VIPs, 2) ensure that VIPs weren't live on both boxes if the other unit came back up, and 3) ensure that a single box could handle all of the load. The recommendation to do active/standby was really motivated more by efficiency and simplicity of configuration. That of course has changed with 11.x with DSC (device services clustering) and traffic groups.

You still have to manage capacity though.