As mentioned before all branded cells are good for the use they are for, but they are called rubbish/crap sells when used for the wrong application.
Branded cells very from approx. lowly 2/3a output to 20/30amp output, most ebikes use a 15a max rated controller so usually lesser/cheaper branded cells will be used.
It is only when the end user modifies the bike with a higher rated max output controller that the battery problems start to arise, as the controller output asks too much of the cells which simply can't handle the load asked.