Okay here are some unarguable facts about ROTJ...
- It has the best epic battle: Endor. Yavin and Hoth don't come close.
- It has the best freaky alien creatures: Jabba, Bib, Ackbar, Salicious, Nunb etc. Nothing in the Cantina comes close and the Wampa was so bad it couldn't even be shown. The best ESB could muster is a blatant sock puppet in a hole.
- It has the best non-vader villain: Palpatine. Cushing is great but not a patch on McDiarmid. We all love Fett but you can't really suggest he's better than the Emperor.
- It's got the best use of the Falcon. Without the Falcon kickin' ass as the Rebel lead fighter in the battle of Endor it wouldn't be half as iconic. The camera work on the Falcon in ESB pales next to Jedi and the Falcon in ANH barely moves.
- It's got the single most exciting chase sequence in cinema history: The speeder bike chase. A masterpiece of sound, photography, design and FX.
- It's got the single greatest use of a Lightsaber: Luke flipping up and catching his shockingly green sabre out of the air. I won't try and argue it has the best duel as the Bespin showdown has that honour (Emperor's throne room comes close though)
- It's got the best FX. If you think it doesn't, you are probably confusing memories of the SE in your head with the GOUT. Go look at the GOUT Bespin or many of the shots from the GOUT battle of Yavin.
- It introduced force lightening. An iconic special effect and an iconic representation of evil.
- It's got the most 'scale' of the three. Epic locations, epic battles and a huge cast of diverse background characters.
There are other points I'd be tempted to make, such as it has the best pacing but I'll admit that that could be argued against. F*ck it! It does! The opening to ANH is painfully slow and ESB is very static in the middle (Asteroid interlude while Luke is jogging round a swamp). Jedi's pace never lets up! xD
As I said (Apart from the last one) the above points are unarguable facts but let the argueing commence anyway...