Hi guys. The bearing on extrusion noise is actually fairly minimal. I've put about 1.5 kgs of filament through the printer and there is no sign of wear. The majority of the noise is from the belts, the motors a close second. Overall the printer sits between the 3DR I built (filament drive, very quiet) and my Huxley which is very noisy, I can't run prints overnight on the Huxley as it's heard through the house. The Cherry Pi is fine. You could run the 3DR in the room you sleep in though ! If you look at the amount of up and down movement on the towers during a print it's actually quite small. I am running at about 80mm/sec overall with 250mm/sec travel moves. I'm sure it will run faster. It is very accurate. I have had some stunning results using spiral vase. A full size (300mm tall) twisted vase came out with out a blemish, it's difficult to tell it was 3D printed and that was with cheapo Chinese filament.
Andy
Andy