You can find numerous profiles on the Rig Exchange with volumes that are all over the place.
Well, some people (like me) prefer the flexibility when recording. There are tones and sounds I could never achieve with the KPA alone specifically because its effects capabilities are extremely limited by comparison.
I stand corrected. And I can see, from a recording standpoint hub, the axe could be a great tool. Strictly from a guitar rig standpoint, or the author of this thread, it comes down to, what effect possibilities would he be missing if he only had a KPA, not counting the advanced reverbs that are coming out any day now. For him, if he is used to a standard pedal board with traditional effects, the only thing he might be missing on the KPA would be overdrive pedals, which are in the plans to be developed further on the KPA, apparently Kristoph confirmed this last month. However, from a price standpoint, the Axe is what $3500, and then you still need the upcoming foot controller?! Likely $4000+ for both. For $3000 one could buy a powered KPA with the Remote and the line 6 HX Effects.
The commercial profiles I use seem to match volume wise. However, the profiles out there that don't match volume wise, one volume tweak and save and you probably won't have to worry about it again. I'm the sort that likes to toy around with where I set the gain. And with the KPA, I can play around with the gain of the profile and not have to compensate on the volume, let along go back and forth and compare it with another profile to see if the volume still matches. For me, at least, I never find myself playing the volume matching game during a soundcheck, and I always used to have to do that with every other multi-effect device I've used.