Here are my complaints about a Brother LED printer (HL-3170CDW):

Rasterisation:

- It supports PostScript, but the rasteriser is so slow it's a problem. If you print a PDF without any transparency in it it's fine. If you print a PDF with the slightest bit of transparency in it, expect a 30 second delay of the "Data" light blinking per page. This destroys the print speed and probably wastes toner due to not having the next page ready in time.

- Its official print driver isn't just a PPD but has some binary blob Linux executable configured as a filter. This is obviously completely unusable on non-x86 platforms. I assume the object here is to rasterise stuff on the host before sending it to the printer to avoid the above issue, but it is a proprietary solution.

- Even using the official drivers on Windows, plenty of documents take noticable time to rasterise per page (e.g. heavy PDFs containing high-DPI scans taking tens of seconds per page), and you still don't get the rated print speed. So the above doesn't fix rasterisation time anyway.

The consumables game:

- The toner cartridges for this printer are NOT chipped. This is good. It's actually incredible how it works; there is a 1 bit mechanical 'register' on each toner cartridge which comes set from the factory, and when the printer senses it, it clears it mechanically and resets some settings such as page count since last cartridge change.

- However, after accidentally buying the wrong cartridges for a newer kind of Brother printer, which had a very obvious set of electric contacts added, it's become clear that Brother is now chipping its newer toner. This cannot bode well IMO.

- Furthermore, the printer will refuse to print after a certain amount of time with a given toner cartridge. Sometimes it will detect there doesn't seem to be toner in it and you can fix this by taking out and shaking it. But, as per the service manual, there is also a hard cutoff after which it just won't print (unless you use the service mode to make it pretend you've inserted a new cartridge). According to the service manual, this is because there is a 'bias voltage' which needs to be adjusted over time as a cartridge is used, and this is reset when you insert a new cartridge. Hence why they have the 1-bit mechanical register. The problem is that their bias voltage lookup table with respect to page count so far seems to run out after the rated number of pages, so it just refuses to print after that even if you have toner in there. You can use service mode to reset this and make it act like there's a new cartridge in there, thereby resetting the bias voltage to the initial value, but I assume this is done for a reason and would lead to suboptimal results(?). So the effective result is that Brother LED printers will automatically demand a new cartridge after a certain number of pages, even if toner is remaining.

I'm currently substantially more happy with a Canon G650 tank-fed inkjet. It's been about a year now and I still haven't had to refill it, which means it consumes consumables even more slowly than the Brother. Of course one of the great things about tank-based designs are they can't be chipped and the ink level monitoring is open-loop.

I will also say the Brother is now unusable for colour printing, as it comes out all garbled. Unclear why this is, perhaps it is due to some bad third-party toner (I never buy genuine), so I'm not really holding this against Brother, but it is another downside in practical terms.

IMO printer manufacturers should be banned from selling print cartridges, and should be required to publish specifications for their manufacture instead.