Final Fantasy X is still as important a release today as it was in 2001, showing a still-unmatched level of emotion, storytelling and easy to pick up game mechanics. People bemoan that the characters are whiny, that the story was unoriginal, and a linear feel but this, for me, was the last great Final Fantasy after the golden age of VII, VIII and IX. You can easily put over 100 hours into X and still have plenty to do, especially with the inclusion of the international features like Dark Aeons, Expert Sphere Grid and optional bosses.
X-2 set the standard for future ATB systems for battle mechanics, and it's clear that XIII is a clear evolution of it. The battle system is fluid, fast and intuitive, a big step from the last ATB game, FF IX. Although weaker in terms of story and gameplay, X-2 makes up for this with a raft of content, secret endings and, especially in this release, the addition of extra Dress Spheres and Creature Creator, another feature seen later in FF games.
Both games are not without their faults though. The voice acting is still under-par but then you could also say that as this is first game with full speech for all scenarios, it's no wonder it was one of the weaker areas. Given that this is a HD remaster, rather than a re-release, I would have anticipated that more effort was put into other models apart from the main 7, Seymour and Jecht but it's still lovely to see the work done on the main models, especially with speech and animations.
All in all, a great release and a timely one for people who missed on the PS2 release over 10 years ago.