When Kemper first put out Purecab I did tests and discovered for high gain tones it was not an improvement in sound with a good profile, for my taste.
I put an extraordinary amount of effort into perfecting my profiles. To understand users perspective I have been asking if they use Purecab or not.
If someone is using Purecab by default I feel they are not getting an accurate representation of my work.
Purecab can have it's place but the Kemper ships new with it on by default and I think this needs to be made more obvious to the new guy.
There are a lot of things to learn with the Kemper and I think this should be one of the first.
All the Best,
LiveReadySound
Edit: Purecab is in the cab section and output menu. The output menu is global, this is the one that is on by default. The cab section Purecab is per rig and overrides the output setting.