I am Patrick and I switched.
Having been a long time user of may line6 stuff, I got a chance to buy a used kemper rack last week. I had read about it for years and now I felt that finally the time was right to switch. And so I did, but I didn't switch completely. In every boys life there comes that point that he has to decide which road to take, or in this case, what would be the main device of ones gear. I was already beyond the point of decision on the helix path. I bought one, and have been using it extensively in the last years. However this FOMO (fear of missing out) kept on hunting my mind, so I decided to give it a try and buy a KPA.
I fell in love the moment I first switched on this wonder of electronics, and have been playing it for a few days in a row. Gradually the idea grew that this should not have to be a 'one or the other' thing, but might go towards a 'best of breed' situation. The weak part of the kemper is the use of the effect chains, but what about a way to eliminate that. The Helix's weak spot surely is the amp and cab simulation. I tried for ages to get the amp settings right, to have the one crunch patch sound as loud as a clean one and just at the moment one needs that the most, during live gigs with some higher volume, you discover that it is not right, yet.
Although I love playing the KPA as a 'stand-alone' device, the real deal is hooking it up in combination with the helix. On the down side, this introduces a lot of choice stress, surely with all the profiles and rigs the Kemper has to offer, in combination with all the stomp-boxes the Helix has. I foresee years of evenings working on patches to find the right sound.
I am Patrick, I didn't switch but I made a new friend for live.