Am using Netflix with a 55LA6900. Seems to be working work fine. Couple of notes/things to check:
a) Not all Netflix shows were originally HD sources. Make sure to check PQ using a Netflix HD show that was originally an HD source and is being provided by Netflix in HD as well. Compare with a non-HD Netflix show.
b) PQ settings are input specific. Check that the Internet/Netflix input PQ settings are correct.