I'm re-watching all 6, just finished 3 last night. I did this about a year ago and I liked 1-3 better than the dull, slow action 4-6.
I was never a fan growing up but I believe people who loved Star Wars as a child, thinking 4-6 would be the only movies, feel they're superior due to being a kid at the time. I was basically going through all of 1-6 as an adult for the first time and the older movies just felt slow and action-less. Anakin felt much more powerful in the first 3, so was everyone else. Watch Anakin swing a light saber in 4-6, he's like an old man. Sure, it was made in the 70s, maybe that's part of the problem.