Personally I favoered KH2 over the first.
But really they're both good games. They both have excellent graphics, music, and storyline (Thanks to Square) and surprisingly even with Disney characters with Final Fantasy characters the story stuck together. I was bit worried when I first started playing KH but it turned out to be a good experience. ^^
..although the ending kinda left me thinking "WTF" Mickey Mouse kicking Heartless @$$!? That was kinda funny. LOL
Then there's KH2. I loved playing as Roxus, no Disney chars for a while. LOL
Even when you resume as Sora it was great. I loved the new battle system with the Drive and the Reaction command. ^^
What I really loved about KH2 is the additional FF party member, Auron!! Woot!! LOL
I wish that Square Enix will continue on the series adding more to anything that follows...which they will, cuz they're Square Enix. XD