I've purchased several of these now for my trusty Brother printer. I use the same toner for both my personal printer and the one at work. The ink is consistent in these cartridges. From day one and until long after you see the low toner light go on, this cartridge keeps going strong. My only gripe is more with the printer than with the cartridge itself. I hate having to reset my printer to allow more pages to be printed - I get a lot more out of the cartridge than my printer thinks I'll get. I can't say how many pages of printing I get, but it's an awful lot. I go through many, many reams of paper between refills. As a teacher, I am constantly printing and both the printer and the cartridge work perfectly for my purposes. I find that removing the cartridge and shaking it (gently, side to side) helps to get more mileage out of it. With all the cheap printers/expensive cartridges out there, this one's worth the money.