Good mechanics, too much fan service
Final Fantasy X was my favorite of the series. In particular I loved Yuna - the summoner who faces difficult choices with a grave dignity, no matter what she is asked to sacrifice. Unfortunately, in X-2 she has apparently decided to get rid of her previous personality entirely, in favor of some unholy combo of Rikku (who is super annoying here... and I didn't mind her in X) and a Spice Girl. I'm not arguing with the concept of character development - of course Yuna would have changed after being relieved of her burden at the end of X. But the development doesn't feel organic, it feels like fan service. Yuna would not wear hot pants, I am sorry.
The mechanics of the battle system are actually great, though the dress-up concept is strange. Look, I'm a lady, and I was insulted by all of this. I'm fine with a regular battle system that doesn't involve playing dressup. In fact, the battle system has a lot in common with FF XIII, which for all its faults has a great combat system.
There isn't much plot, and what there is does away with a lot of the developments in X. There are multiple endings, but in order to get the best one you must get 100%. Forgot to look in one corner in the opening 5 minutes? Sorry, you aren't getting the ending you want.
I'm going to buy X and X-2 HD when they come out, but I can't say I'm going to be replaying this one...