Long time no updates on Dollo, Prometheus and my related project, filaswitch g-code post-processor has been taking my time. But I've been meaning to do 2 things: change X and Y stepper drivers to something better than A4988's and use sandpaper to smooth the X and Y rails.
Finally got some time and swapped the Trinamics TMC2100 drivers to Dollo. The difference in worst-case noice level is huge: A4988's had that certain speed area where the movement would just resonate very loudly and it was not nice to listen. With TMC2100, smooth as butter. TMC2100 also have interpolated 256 microsteps, meaning that the controller board sees them as 16 microstep chips, but internally they do 256 microsteps. This should make round surfaces smoother as motors move in smaller increments.

Also took the rails out and sanded the grooves. Especially the joints needed some cleaning, it's been evident that they do cause bit of artifacts to print surfaces. Also checked the motor gears for print artifacts, something I should have done when I printed to gears.

Result seems much better, at least regards the outwards aesthetics of the printer; seems fluid and doesn't sound like something is going to break any minute. Doing 3DBenchy right now, will post result after.