I first bought one roll of Black Filament from eSun a while ago. It performed very well on all 4 of my currently active 3D Printers the CR10, the Monoprice Mini, the BIQU Magician and now the Ender 3.
This filament continues to amaze and perform regardless of which machine i load it into. I haven't had one single failed print.
Also to note, if you wrap the left over filament along with its dehumidifying gel, and put it back in it's original box and store it indoors in your living space, it retains its slight elastic quality even after it's stored away for a while.
How do you test this? Take the leading end of the filament, and try to straighten out a short length (an couple of inches) by plying it with your fingers. A filament that isn't brittle yet will respond and try to straighten while a brittle filament will snap off almost immediately.
My old filament roll continues to deliver stellar prints alongside the new rolls that I purchased a few weeks ago. I have several other brands of filament stored the same way, but unfortunately, I see that they've gotten brittle over time in comparison.