Back in August I assembled a Prusa i3 MK2S kit. It took about 8 hours in total - I think I read somewhere the world record was 4 hours? Anyway, I took my time with it and it was pretty enjoyable. The instructions were easy to follow, and after doing the initial calibration, the printer told me "you did a good job!" This printer now lives at a new makerspace in Kyoto called Kyoto Makers Garage.
Here's a time lapse of the build.
Looking forward to one day putting together an MK3!