If you'd have asked me in 1983 when I was twelve I would've rated ROTJ, ANH & TESB in that order of best to worst, as for as I was concerned at that age ROTJ was like the best bits of the first 2 movies and then taken to the next level. asked the same question at age 15 after repeated viewing Empire would have had a slight edge over Star Wars and ROTJ would've come in 3rd.
Empire just had so many more layers to it that became apparent with age and repeated viewings.