FF7:
Liked: Storyline, Music, Materia
Disliked: Plot Holes .. and I didn't like Aeris at first ..

FF8:
Liked: Music, Junctioning was kind of fun for me
Disliked: The whole confusion about who Ultimecia actually is and why she wanted time compression ... and drawing took up a lot of time

FF10:
Liked: Sphere Grid, Switching, Music, Story
Disliked: Cloister of Trials

FFX-2
Liked: Battle system
Disliked: Almost everything else. The music killed me xP except for 1000 Words.