I know that riders are 99% satisfied with KMC chains, but I had a problem with the first one I used. It had a bum Missing Link (see photo in post
#5 above) and it skated over the position 2 cog on a 9sp system. I adjusted the indexing over and over, trying to get the skate to stop. It wouldn't skate in the work stand, only on the road.
I examined the cassette closely, no signs of wear. The KMC chain was not worn excessively either. I put on a new Shimano chain, and the skate is gone.
An argument for using the same brand chain as your cassette. But I used SRAM chains for years before the KMC, worked fine. Won't use KMC again.
To reiterate, I know most people have good luck with a KMC chain, but I didn't. Moving on!