The Stage has had teething problems but both the hardware as well as the software issues seem to be ironed out (speaking of FW 7.0.5).
Playing Kempers since 2012 I fully trust the company because I've seen and experienced how they deal with problems.
I’m with Ingolf here. The company are great for support and their products are solid. I’ve been gigging my 1st KPA since 2012 and it’s been rock solid. Whatever issues you are having the Kemper team will sort them