I'm with Remon here, after the Pharos and Giruvegan/Crystal, I was pretty damn happy to not have a another 5 hour dungeon to travel through.
I actually hated Sin's dungeon, cause most of it made little sense... I'm walking through a foggy area, now I'm in a weird mechanical place that's like a maze, now I'm collecting crystals for no goddamn good reason, now I'm listening to Tidus whine like a little bitch to Jecht, fight the Final Aeon, but I have Anima and Legendary weapons so he literally goes down in two attacks, the intro to the fight was longer than the actual battle, have to fight all the Aeons who get 1 hit KO from my party, now I fight Yu-Yevon with my party permanently auto-life, I zombie Yu=Yevon and watch him kill himself, I watch a very boring and overly melodramatic ending where Tidus can't just gently fade away, he has to jump off the airship so he can high five his old man which sucks the drama out of the game. A boring speech from a character follows, and then we get this weird scene of Tidus swimming under water. The End
I'll take a short dungeon with a four part boss fight that lets me get a judge on my side for one part and ends with the boss transforming into a cyborg Bahamut over that Sin crap.