Just so I understand better in comparing the Kone/Kab with the Line 6 PowerCab...
Each of them are capable of serving as FRFRs to play studio profiles. And, each of them can be used as real cabinet powered by a power amp. And in that case, they can be told to be a particular speaker i.e. a V30 in one instant or a GB25 in another.
The Line 6 PowerCab looks to have self powered options right now whereas the Kemper solutions needs a power amp in front of the cab. Also, unless I'm looking at it wrong, the speaker modeling lives in the PowerCab so you could use it with a Kemper and power amp (or a tube amp?) and have it sound like any number of cabs. It seems like the Kab/Kone is dependent on interacting with the Kemper brain or can the cones be told what to be without having to connect to a Kemper?
If the Kone/Kab needs the Kemper connected, then it's less interesting to me. What would be the most flexible is a cab that could virtually change the speakers no matter what I connected to it. So the modeling would need to live in the cab I guess. I THINK that's how the PowerCab operates but I don't know.