I have two sets of them in fresh bores. The first engine had 10,000 miles on it when I pulled it to install the second rebuild. The second rebuild currently has 6,500 miles on it. These are both N/A's.
I had no problems getting the rings to seat. However, I was quite meticulous with break-in....none of this mindless "drive it like you stole it thing." Both engines run very strong and I really put the coals to them (once seated)....as much as an N/A can.
I am currently running 10% hydraulic fluid as fuel in the second one and running it hard and no problems noted.
The company which builds these pistons is in Malaysia and they produce a LOT of industrial pistons for tractors, trucks, etc. THAT is why I felt reasonably confident to purchase these....and so far.....all is very well.
And, yes, I scored a pair of Kolbenschmidts for the Eco diesel....although I wonder if I really needed to.
Just my take for hard earned dollars.