My main issues:

* one day remote printing no longer works, you need to set it up again or even get into prolonged debugging session

* remote printing works one ane device but not other

* one color toner cartridge on a color laser printer is empty or near empty, printer refuses to print without all manners of overrides on the local control panel, making it unusable for non-technical users

Well, the last point is basically sabotage by the manufacturer to make you buy more stuff, as it can print B/W perfectly fine or with slighly less quality until that one cartridge is replaced. But I guess that kinda proves my original point. :)