Up till now I only ever bought REAL Brother cartridges, but these are no-name knockoffs. The copies come out mottled with black spots, which never happened with the real ones. The one I opened today (the LAST one, finally!) had leaked all over and made a big mess. I will never buy these again.
If you care about the look of your printing, only use the real Brother brand cartridges. These are cheaper, but your copies will look cheap, too.