I have played through the game 5 times, and only used Raine in the first playthrough, because I was a n00b. She is slow, and can't damage enemies for -BLEEP-.

My favorite party is Genis, Kratos/Zelos, Lloyd and Presea OR switch out Genis for Regal (with a Lvl 4 EX Gem equipped, so he gets the 'Guilt' ability). Those two parties rawk.