My first experience with an SRAM chain was on a brand new bike. One of the links was missing the roller. Obviously a manufacturing defect.

My second experience was a replacement chain for an old beater. The chain, neither top nor bottom of the line has rollers with rough looking edges. I'v only been using it for a few months and hope it does not wear down the chainring or cogs. Still, I wonder why the rollers are not uniformly smooth.

I think I may stick with Shimano chains in the future.