I got a KMC 8.93 chain today for the bike with a 6 sprocket cluster. There's also a KMC Z-51 chain but it got terrible reviews. I also noticed that a lot of reviews for Shimano chains weren't all that great either. This leads me to wonder if the quality of Shimano chains in general is dropping. Is it?

If Shimano chain quality is dropping then who is making better quality chains?

Cheers