The toner is very expensive and there is no incentive for returning used cartridges. The process for receiving "free" shipping is somewhat deceptive, as a third party is involved that asks for a monthly fee for the privilege of "free" shipping. The cartridges do arrive quickly and are easy to install. The print quality is good.
Very convenient to order the four colors together. I use more black than colors so would have preferred the black cartridge to be the extra large size. Otherwise great toner for a really great printer.
I was cleaning out our air conditioner return line and left it overnight. That part of the garage got flooded with water and the box of toners completely soaked. Fortunately they're in waterproof canisters so they stayed dry.
Haven't tried them in the printer yet but hopefully they work.