I printed these on a mini Kossel and you need a printer that is well-tuned to print these. As such, the tolerances are very tight. I use a length of extrusion to manually "burn-in" a newly printed slider. the friction softens the plastic a bit and smooths the feel.
I then use a gcode program to "burn-in" the slider starting at 50mm/s and working up to 400mm/s. I have to run the printer as a Cartesian to get these speeds.
I don't use the 3mm nylon screws Bill uses. I found they add squeak. I have run these at over 600mm/s (https://www.youtube.com/watch?v=DABFczCJ2QI).
Time will tell if these are viable, but my accelerated testing says they will be.