It's the last main series Final Fantasy that I really liked. The story was suitably quality, with some nice twists and turns, not to mention good use of plot points to promote themes. The characters were not universally well developed, but were on the whole a generally likable group of people. The combat system is my favorite in the series, main iteration or not, the presentation is likewise stellar, etc.
Even some of my complaints about the game are neutralized by what I like about it. The game's linearity, for example, makes sense in the context of the game's story, especially towards the ending. The voice acting isn't always what I'd like, nor is the writing quality, but it lends the game a feeling of adolescent awkwardness that fits the game surprisingly well. Seriously, I'd rather have the occasional awkward phrasing than a somewhat better cast of actors simply because the occasional awkward moment wasn't that bad and managed to convince you that this was the story of an angsty teen from their point of view.
In retrospect, the main problem I have with FFX is the inability to skip cutscenes, even if you Game Over and have to watch them again. This also makes it harder to just jump back into the game if you want to experience the gameplay. But considering how loads of early PS2 games had this problem, I';m not going to be too harsh.
8.5/10, have played multiple times and will play at least once again.