I don't have anything to add other than I really lust after a Turban 140mm.......I think it's all in the kinematics....linear bearings, finely machined surfaces, tight tolerances. Will probably do nothing to increase precision (or that 99% of shooters cannot outshoot what a Rockchucker or Redding or Forster can do)
But they are super nice. Talking about the Prazi here, haven't seen the others you mentioned.