Our alternative to the original

We (two full-time teachers) use since about 5 years Toner of Hainsberger in a Brother DCP-9055CDN with an annual print output of around 12-15000 pages black (90%) and non-ferrous (10%) blended.
We have already bought later individual toner (as that voted stories here), but also have the 4-sets (1x black, 3x colors) bought.

We initially tried several other "replacement toner", had since but always different problems ("leakage" - whole printer eingesaut with blue toner or very low filled cartridges (black) who've been empty for 2,000 pages).
With the brand Hainsberger there gabs so far no such problems.

The print quality is indistinguishable from the original, in our opinion, and of the printable page count, we found no difference.

Tip: We leave the cartridge after the message "Toner exchange" even a couple of weeks longer in the printer and insert the cartridge back manually. This allows us to loose again print 500 pages before seeing a deterioration in the printed image.

Conclusion: For us, the best ever price / performance ratio. Our printer refuels only Hainsberger :-)