Doing the print heads on the Brother is also a pain, you have to virtually dismantle the thing just to get to the cartridge cradle and then it is all uphill from there. Last time I did a cartridge change, about three years ago, I filled the old ones up with cleaning fluid and printed a load of pages till all was clear - I just kept using the same paper over and over.
When the thing did its diagnostics with the new cartridges, as it is wont to do, it will not allow you to use it till it has done, all was well.
I have just been looking at mono laser printers and I can buy a few different models for £10 less than Brother are asking just for cartridges. I generally only print letters so it might be an option to consider.