Depends from movie to movie, edition to edition. Hd-Dvd editions of King Kong or Doom, for example, have a visbile and (to me) disrturbing judder. Most blu-ray don't have (still for my eyes) judder at all.
Do you know if the firmware is the same for USA/European models? If so, can please someone be so kind to mail me the file at email@example.com (get rid of.nospam to write)? Please .. it will be great.