I have written previously in length why Final Fantasy X is one of the worst games I have ever played in my life. Even worse than Final Fantasy XIII. (The tl;dr version is: Everything that FFXIII did wrong, FFX did before it. Every complaint that you may have about the former is true for the latter. In fact, FFX is IMO even worse in almost every such complaint, and it even introduces a couple of its own.)
What I find curious, however, is that I seem to be the only person in existence who thinks this. Every person I have talked about it, either online or in person, who has played FFX, defends it.
Curiously, none of them seem to be able to give any rational reason why. For example I asked one such person, who I was talking to in real life, to name even one thing that was wrong with FFXIII that was not equally wrong in FFX. The only answer was "the battle system was better in FFX." No, seriously, that was the only answer they were able to give me.
I actually took that as an indirect admission that FFX was in fact effectively not any better than FFXIII (although I didn't say it out loud.) If the only argument is "the battle system" and nothing more, then that's pretty much the same as "effectively equally bad".
(As a tangent, it's a matter of opinion which game's battle system is better. In my personal opinion there isn't much of a difference, but I think I enjoyed the one of FFXIII more.)
Why people defend FFX is beyond my comprehension. It's an absolutely horrendous and frustrating game that does not deserve the bear the name "Final Fantasy" and does not deserve the category of (J)RPG.