Eleven Rack had the best feel amongst the modelers I tried. IMHO ELeven Rack felt better than AXE II, but when I profiled my amp and as I was comparing the profile with the real amp, I realized that Eleven, AXE FX II , POD, can have a very good feel that someone can easily get used to and be comfortable with even though it's exaggerated specifically in the Sag department, either too much or too little and it varied significantly in a way not consistent with how real amps react when the string were hit harder or softer .
Add to that unusable/unnatural hi frequency response in the other modelers, to my ears and judgement, the Kemper is simply in a much higher league. Based on sound and at the surface it might seem that the difference is minor, but when you consider the inaccuracies, by which the AXE FX II amp would react when cranked or guitar played with varying dynamic, you will realize how unrealistic and off the modeling is.
Try a twin reverb model in any of the other modelers including the AXE FX II , crank the gain , and you will quickly realize how inaccurate the modeling is, because it won't sound or feel anything like a real twin, and my guess would be that the twin might be the easiest amp to model.