brusky, which profile did you compare with? Just curious.
This
Tested clean and edge of breakup, no effects. Single coil and humbucker. At first my ears heard slight compression on the Kemper profile. Then i dialed in the eq to match closer both amps. It may have been due to the loop but the Ruby sounded more like in a big room though i turned the 'room' knob to 0%. overall not a big difference with clean. For sure not a game changer. For edge of breakup the Kemper profile felt to me that had more punch. Also the Ruby seem to have less headroom overall. I had to turn down the rig volume and turn up the loop volume to level. Anyhow this was just my amateur test. Maybe the UA pedals are more design to use on a pedalboard rather than in the loop of a Kemper/modeler. But for my workflow it would need to really outclass the Kemper, which i was not able to prove. Maybe one of the pro's here can do another test and show this can sound best in the effects loop.