I put 150 hrs on a 570 with no show stopping problems.
570 good points.
Better (like way better) electrics. Stronger battery, rectifier, relays on everything. Just better all around.
Combined motor and transmission oil. Plus a sump. It's a way better setup than the KTM.
Hard to get aftermarket parts for, i.e. fuel tank, rear rack.
Runs hotter. Heat is captured between the motor and the sub frame.
I owned a KTM 530 for a couple months. Even though the valves were set correctly. That bike was a killer to start when warm. It stranded me in the middle of no where a few times.
The berg started and ran all the time. Besides there are really nice 570 on CL and the flea market for 6500 to 7500. That is a good price.
If you ask me, I'd say that two wheels is all you need.