Father in law has a couple of extrusion types 3D printers. The first one he built himself from a threaded bar frame, spare motors/belts and an arduino plus the usual open source controller software and motor drivers. The second is a kit (Mendel 90, £600) which his local makerspace group bought together and assembled under his guidance. TBH, I think building, getting them to work and then calibration/improvement is more fun than actually printing things. I have no interest in buying a ready-made printer, especially as the latest commercial kits are really only starting to solve design problems we fixed a year ago, and there's still a list of dozens of improvements for the self-build mk2 that's on the cards (mostly around auto-re-calibration after transportation, rigidity, better, more even temp control which is important to the extruded filament type printers, and some software changes to smooth direction changes (configuring ramp-up/down on the motor control, and detecting and eliminating resonant frequencies somehow).
However, strength tests of printed parts are quite impressive, accuracy is plenty good enough for just about anything you'd use one for.
I've thought of a few one-off practical uses for the printers, but not enough to justify building my own at home yet, especially when I can just email sketchup models to my FIL and pick up the parts next time I see him.
