we have both!
they are both working just fine.
we had an issue with the jetcat 160 kero start and it took 4 month turn around repairing time [:@].
now, with another issue to repair in the engine we are waiting almost two month and still counting [:@].
we had an issue with the evojet turbine ecu, and two or three phone calls to arno, evojet owner, helped us
to determine the problem. one week later the post office man came with an envelope which a new ecu was inside.
THIS IS WHAT I CALL SERVICE!!!!
I'm speaking about jetcat in Germany not in the U.S. !
I have no experience with KT (but I have an intention to buy the new 180 in the future) but from my friends experience it is very fast and good.
We have experience with AMT NL and wren turbines, also first class service.
All the above is based on our self experience, so maybe you'll hear some other different opinions.

Good luck
Avi