I think I'm gonna be THAT guy (that's right, no one said what i'm about to say) but I don't find the trilogy all that good from a cinema perspective. From an entertainment point of view I totally understand (some of) the success, but not to the extent of a good movie experience. Peter Jackson proved to be a much better director in King Kong than in those movies to be honest.
First: literal translation of languages instead of adaptation. Movies are made by images first and foremost. They are not books. Kubrick's "The Shining" is a perfect illustration of what I mean. The Lord trilogy acts like it's a direct transcription from the books and many of the images serve no purpose rather than just confirming what we have already heard a given character say at some point. Take, for a contrary example, the Batman Returns ball scene with Wayne and Selina finally realizing who each other was. No spoken explanation whatsoever and you are carried along into the tension. Amazing! In Lord of the Rings almost 100% of the action is explained through dialogue because the movies, for the most parts, do not believe in the audience's intelligence. I mean, come on!, a guy lights a lantern or something like that and someone shouts: "the lantern was lit!". For puking out loud sake, how can someone bear this kind of thing?
Second: low tension, and that affects the last movie the most. There's nothing that makes you fear for the destiny of any of the main characters or for their success. Ok, we know the books and how everything turns out, but the last movie is almost unbearable to me because it is just a loooooong series of activities that carry no surprise or engaging moment, at all.
Third, and this is probably a fault of the original material so that could hardly be helped in the movies: a much too masculine world and females have almost no say or good actions, except for the second movie. This bores me to hell.
So, having said some of the things that bother me, let me rate the series from a quality perspective and to also mention why I think Two Towers (the one that received my vote) is the only one that can be called actually "good":
Fellowship: 5 or 6 out of 10 - entertaining but not remarkable in any way. The poor pacing kills much of the excitement. Nice images, though.
Towers: 7 out of 10 - good story development, actual tension (you are going to really fear for the fate of many here) and some actual, relevant meaning (if I can remember correctly after all these years) in the possibility of genocide, which is an actual and recurrent theme even in the modern world, unfortunately. Plus, the Ents are awesome. It drags a bit though, for it's own sake.
King: 2 out of 10 - my goodness, how did this horrible piece of crap get to be so successful? Boring, with no pace whatsoever, and all the tension built in the second one disappears into dust, as the action is so horribly just "placed" there and you are sure from the first moment that nothing can go wrong. It serves mainly as a catharsis moment for the fans, who can only sit back and enjoy an almost thrill free ride. And lots, lots of useless dialogues to explain what we can CLEARLY see on screen. Again: So. SO. Boring.
As you can see, maybe my vision of the whole was affected by how horribly it all ended, but I cannot agree that this can even run for better ever movie trilogy. If you want to compare popcorn trilogies, Back to the Future, just to name one from the top of my mind, is waaaaaayyyy better.
Wow! Impressive! I've never seen someone be wrong about something subjective before. I didn't even think it was possible!
My Console Library:
PS4, PS3, PS2, PS1, WiiU, Wii, GCN, N64 SNES, XBO, 360
3DS, DS, GBA, Vita, PSP, Android
Top 6 this generation:
Bloodborne, Sekiro: Shadows Die Twice, God of War, The Legend of Zelda: Breath of the Wild, Dark Souls III, Red Dead Redemption II, Rock Band 4