Yeah I also loved Jedi since I was a kid and was kinda shocked once I grew up and started reading online that many considered it a weak film and that Empire, which I personally found to be the least compelling entry of the original trilogy, was the best.

All bow down before the KING! The answer to me is The Return of the King hands down, no contest. But... this answer is strongly biased, because The Lord of the Rings has a capital importance in my life: I read the trilogy in my early 10s and the movies were released shortly after, so I was exposed to the Tolkien universe in a big, big way and it had an equally big influence on me.

Besides, at that time I was a kid/teen living in a lower to middle class family with almost no access to technology, apart from one console with two games and a VHS player with four or five movies, so reading the events of the books and then watching them captured in a such a magnificent way was a magical experience for me back then. When I first got a VHS of The Fellowship of the Ring, I watched that movie literally once a day (for a total of tens of times, more than 50 for sure). Also, I used to go walking around my house every afternoon, while creating stories in my mind with the Middle Earth as the setting and my own character in the center of all the adventures. And as time went by, I started to add more original characters and creatures, and then I left the Middle Earth behind to create my own world, and I even invented my own runic language (a very basic one, but still). At some point, I had so much original content in my mind that I needed to express it in some way, and that's how I started the activity that has conditioned every single one of all the important decisions that I've made throughout my life: writing. And all of that started with The Lord of the Rings, so if there's One Bias in me to rule them all, this is it.

On the other hand, if I use the Force to try to hold that bias back, the result is still the same, but much less one-sided, because Star Wars has an excelent lore, fantastic ambientation and very good characterization with great special effects, and of the eight movies of the main saga that I've watched (I haven't had the chance to watch the last one yet, unfortunately), I've liked them all, including The Return of the Jedi. However, Star Wars in general is not as good in storytelling and dialogs as The Lord of the Rings is. And while a lot of people complain about the slowness of the latter (which is fine, because it's a matter of taste), that's not a problem at all for me, because I can enjoy both fast and slow movies as long as the pace is good, and The Lord of the Rings is very well paced (although The Two Towers is slightly worse than the other two in that regard).

Return of the King, easily.

You are actually fortunate. Just don't know it yet :p 

Seriously though, people on internet screams about how bad some SW movies are (mainly Phantom Menace, The Last Jedi and Solo A Star Wars Story), but the Rise of Skywalker is the only Star Wars movie that is a disaster from a cinematic standpoint

We should create which movie is worse

The Hobbit 3, I forgot the name
Or The Rise of Skywalker

It would be a really interesting thread

I'm sad for Peter Jackson because he was pretty much forced to film Hobbit 3, he had no plot to work there, it's basically a bunch of mindless action and wars that don't have any sort of urgency and tone. It's close to a Transformers movie if anything 

Good thing is I haven't lose my money watching it on cinema, after Smaug I knew there isn't anything else on this trilogy for me 

I never saw Rise of Skywalker and I don't plan to; after how utterly dogshit The Last Jedi was, I bailed on the franchise.

The third Hobbit film is a mediocre piece of cinema for sure, but if Rise of Skywalker is even half as awful as its said to be, I'd still take the former any day.

It is tough but I would vote for Return of the King.

(warning spoilers below)

I love the OG Star Wars trilogy and I think that it is a timeless pop culture masterpiece that defines not only the Boomer generation but Gen X and most of the Miliennial generation. The LOTR was a movie-making masterpiece that in my view told a story that was deeper, technically better written and likely even more timeless than the OG Star Wars trilogy. I think that Star Wars had a more transformative effect on culture and society at large compared to LOTR especially in terms of pop culture references and lasting love of the franchise (which didn't start waning until the prequels came out and were met with disappointment). That said, LOTR did have a transformative effect as well especially in terms of the shift away from sci-fi towards the fantasy genre that occurred in mainstream pop-culture in the mid 2000's.

If this was a debate of the OG Star Wars trilogy vs LOTR trilogy, I would vote for Star Wars by a small but definite margin. IV and V were just unbelievable movies, especially if you can get away from the Special Edition and watch the original theatrical releases (which most people have never seen). That being said, as has been said repeatedly on this thread, RotJ was the weakest of the OG Star Wars movies. It was clear that the creative well that Lucas was drawing ideas were starting to run dry in this movie which only got worse in the subsequent prequels. RotJ is still a very strong movie that gave a really nice conclusion to the trilogy, but it was obvious that the tank was sputtering a bit at times during the movie. RotK, on the other hand, carried seemlessly on from Two Towers with very little loss of momentum right up to the end of the movie. You can maybe argue that the army of the dead wiping out Sauron's massive invasion force in RotK was a bit of an anticlimatic conclusion to the biggest battle in the trilogy and, in my view, wasn't quite as strong as the conclusion of the battle in Two Towers, but this is minor. The battle was still very epic, overall. The whole Ewok arc in RotJ felt underwhelming and even the death-star battle felt a lot less intense than in episode IV. What really saved the climax in RotJ was the arc between Luke, Vader and Palpatine, which was incredible. That said, RotK didn't have any parts that "needed saving": the whole movie ranged between strong and masterful. RotJ had some bigger dips which hurt it overall.

Yikes, considering how atrocious Last Jedi was, this only cements my desire to stay well away from Rise of Skywalker.

The entire 2010s trilogy was a mistake.

Yeah, I watched every Star Wars film to come out in my lifetime at the cinema up to Last Jedi, and it just broke me. Completely ruined Star Wars for me and made me not give a shit about it any more. Modern Disney is poison, they wreck everything they touch.