You should use the Brother toner. Why take my advice? I worked for IBM and Lexmark for forty years in toner and photoconductor manufacturing, in both quality engineering and management roles. Toners are much more complex than they seem, and development of them can take a couple of years because of all these factors and more: melt point, melt viscosity, particle size distribution (electrostatic behavior is affected and that's how the toner is moved), powder flow characteristics, adhesion to the paper, capability using various paper stocks, ship/store characteristics (so it doesn't turn into a brick in your car), fuser release characteristics (the number one cause of printer failure using non-OEM toner is fuser fouling with stuck-on toner). I could go on...