You know...Come to think of it,they are exactly the same.I mean,personality wise,in looks.Everything between Lenne and Yuna is the same to.Lenne was a summener who had to sacrifice herself to destroy Sin,and Yuna was a summoner who had to do the same to bring the peoples happyness.Tidus was Yunas lover and sould stop at nothing to help her,Shuyin was Lennes lover who would do anything to save her.We dont get into Shuyins personality befor he relized Lenne was to die, so we cant say he wasnt a whinny little brat like we all(well,most) think Tidus is.But,Tidus changed after he relized Yuna was to die.He wasnt as totaly a space case and an utter idiot as befor.He was determin to do something.Shuyin was probly the same.I guess you may prefer one of the other,but when it comes down to it...they are the same...