I would recommend FFX to anyone who likes JRPGs. It really is a must play game. Actually I would say that several Final Fantasy games are must plays: 4, 6, 7, 9, 10, 12 are all must plays. I highly recommend them all. FF X is probably my third favorite after 7 and 9.
Here are the things that I really remember loving about FFX:
1) The characters. Even the characters I didn't like at first grew on me. And then there are characters like Auron. He is so badass that it is worth playing through the game to see what happens with him. Also I love that they sometimes say little things during battle. It was a nice touch.
2) The battle system. Every character really does have a unique role and part of the battles are using the right character for the situation and part are just choosing which characters you want to use. It's a great system.
3) Music. The soundtrack to this game is phenomenal.
4) The story. There are a few cringy parts, and there are also some confusing parts. But mostly the story of the game really sucked me in and I thoroughly enjoyed it.
5) Blitzball. I know not everyone liked this (mostly optional) minigame, but I really loved it. I remember playing a lot of blitzball.
Also the game is just really well paced and crafted. I know it is a linear game, but I don't really remembering that bothering me. In contrast FF13 is really linear for the first 20 hours and that irritated the hell out of me. Somehow in FFX they hide the linearity enough that it wasn't really a problem. Also, like most FF games, there is a mixture of fantasy and tech in FFX. You can watch the opening cutscenes of the game for 5-10 minutes to see there is tech in the game. It's just that some places and characters are comfortable with tech and others are not.