I built a Huxley Reprap Pro two years ago. The building experience was interesting, but fiddly. I needed a few spare parts along the way and getting them was slow. It feels very much like a prototype / proof of concept rather than working tool but getting it working was rewarding.

I printed a few things, including a centrifugal pump, from thingiverse as well as a few of my own designs. They usually come out reasonably well, but the finish is not attractive and it usually takes a lot of fiddling up front and more than one attempt. Comparing the quality to stuff I've had made by Shapeways / Materialise there is no comparison - they are infinitely superior.

Keeping the machine operational requires constant vigilance! If there's a kink in the filament, or the extruder loses heat the machine has a habit of self destructing.

A bit put off with home 3d printing, I recently built a Stepcraft CNC Router https://www.stepcraft-systems.com/en/

It's been an altogether more rewarding experience. It feels like a real machine and the results are really impressive. I've not really had anything go wrong with it after assembly. It is quite a bit scarier though having a diamond bit spinning at 20,000 rpm!