Having hurt myself and damaged my bike when a chain snapped with a further five plates with stress fractures I’d never buy a cheap chain or from
eBay/fscebook. I Only buy from my LBS or a reputable on line cycle parts supplier.
yeah the calf and chain ring interface when the chain goes is not a nice one IME.
absolute yes to the buy only from reputable stores, BUT, during the shortage of spares in that period of 5-6 years ago, where chains seemed to become even rarer than groupsets, alot of fakes entered the system, and I bought one from what I thought was a reputable store, which turned out to be fake, and it lasted 6 months during the summer, normally I get chains to last 12-18 months, and occasionaly across 2 winters at least.
course by the time Id fitted it, because I buy one to have as a spare the moment I replace it, plus the 6months of use, it was at least 2 years plus, and Id already lost the receipts and records of it.
so always double check them for the obvious signs of fakeness when you get them, before putting them in the cupboard for later.