Every bit as good as FFX.
As with FFX, it has a linear world, but no linear gameplay. Yay! The fighting system, however, makes up for this. With the fast-paced fighting and awesome job system, FFX-2 became a more enjoyable experience to me than FFX. Plus, there was less whiny Tidus to deal with.
Graphics:
Still looks amazing...better than FFX to be honest. No complaints here.
Sound:
The voice acting is still really good, but the music is a little worse. Plus, now Yuna is a pop-star, so her pop singing got on my nerves. But the traditional battle music and overworld music were good.
Value:
I played through this game 3 times, since it has branching stories, so to speak. The more side stuff you do, the more gets added to the story, and the more you do, the more percentage you complete. And to fully see all of the game, you must get 100% and see the special ending. I did that, and once you do, the story is actually pretty decent and the game is long enough to satisfy.
Overall:
If you played FFX, don't miss X-2. However, if you haven't played FFX, then skip it. You won't really understand what's going on. Even if you hated FFX, at least rent X-2. The battle system is worth checking this game out for alone.