yep couldn't agree more, it's hit and miss.
some come with warranties too, but nothing is guaranteed.
even genuine products that have had aging shelf life guarantee nothing.
something else to consider is the degradation rate of many laptop users' battery integrity and the protocol charging/charge-retention communication between OS and motherboard.
we may think we're getting a new battery, but if the final-product engineering is mostly trash, like the TxxS series of thinkpads 2009-2012, then don't expect stellar quality regardless of battery manufacturer.
good luck