I am an extended edition buff and have a big collection of original ones and all the fanedits from here.
Many extended editions do not add anything to the movie, just add more useless scenes. I will rate the ones here.
Rating criteria: image quality, sound quality, 3x improvement, overall.
Image Quality: 9 of 10
Sound Quality: 9 of 10
Improvement: 2 of 10
Overall: 5 of 10