I'm very pleased with the Monoprice TN880 Compatible Toner Cartridge. It has excellent print quality. My only issue is that I'm questioning if it generates excessive toner waste.
I'm using a Genuine Brother DR820 Drum Unit that came with my Brother HL-L6200DW printer. I love that the TN880 Toner cartridges for this printer and drum unit prints up to 12,000 pages. However, the DR820 drum unit has a very small waste toner compartment that gets filled very quickly and doesn't seem to be designed to support 12,000 pages. I've had to take the drum unit apart twice already to clean out the full waste toner compartment because it was depositing specks of toner over the printed page. I'm guessing I will need to empty it a 3rd time before my toner cartridge runs empty. Total pages printed with this drum unit = 10,640 pages = 2940 pages on the original brother trial toner cartridge which came with the new printer + 7700 pages from my Monoprice MPI Compatible Brother TN880 toner cartridge. I needed to empty the drum unit waste compartment at about the 4,500 page mark, and again at the 7,000 page mark (approx).
I haven't tried running this printer with a Genuine Brother TN880 toner cartridge due to the high price of genuine brother cartridges, so don't know if I would have the same problem. I haven't seen any comments from users taking their drum units apart to clean the waste compartment, nor comments from speckled pages from people with genuine Brother TN880 cartridges, so I hope my post helps others with troubleshooting their speckled page problem. For now, I'll experiment with a different brand of compatible TN880 toner cartridges hoping to find a compatible product that generates less wasted toner.