Regarding the 'private bundle' discussion, I think one point is being overlooked. The BiAmp software allows wiring between two points to be automatically assigned to a CobraNet bundle so the user doesn't have to configure the Output from one box, the bundle number, the input on another box and the bundle number. It does it all automatically, quickly and is very easy to follow the signal flow in the software.
In my opinion, the mechanism of transport is inconsequential - it could be done using private bundles, unicast or multicast. The method of configuration is very easy in some applications (but not all).