After hearing a lot of complaints and some praise for Serah, I thought it'd be interesting to discuss her character.
Did you prefer the XIII-2 Serah to the XIII Serah?
I personally liked both. Although many people argue that she is whiny and needy in XIII, I would like to argue in Serah's favour.
XIII (not XIII-2) spoilers below.
However, XIII-2 improved on Serah's character by fleshing her out. She did mature.
XIII-2 spoilers below.

Did you prefer the XIII-2 Serah to the XIII Serah?
I personally liked both. Although many people argue that she is whiny and needy in XIII, I would like to argue in Serah's favour.
XIII (not XIII-2) spoilers below.
Although Serah does lean on Snow and Lightning, her brand is essentially a time limit for the rest of her life. This in itself is frightening as it means she can't possibly fulfil her goals and must be apart from the people she loves. Furthermore, she will be conscious in 'death' (as Ceith and l'Cie are).
The fact Serah doesn't know her Focus must also be extremely frightening as it may cause pain for others. I am willing to bet that a lot of people in Serah's shoes would find the situation extremely difficult and would therefore cry a lot, suffer anxiety attacks and have to lean on their family.
I admit I wasn't sure what to think of Serah either at first as there is very little we do see of her. However, the scene on the beach with Vanille in which Vanille apologizes to Serah made Serah appear mature and balanced.
I can only find it with a fandub, so Serah's voice is different, but her words and expressions still show maturity.
http://www.youtube.com/watch?v=Dwdr0Oo7YUE
The fact Serah doesn't know her Focus must also be extremely frightening as it may cause pain for others. I am willing to bet that a lot of people in Serah's shoes would find the situation extremely difficult and would therefore cry a lot, suffer anxiety attacks and have to lean on their family.
I admit I wasn't sure what to think of Serah either at first as there is very little we do see of her. However, the scene on the beach with Vanille in which Vanille apologizes to Serah made Serah appear mature and balanced.
I can only find it with a fandub, so Serah's voice is different, but her words and expressions still show maturity.
http://www.youtube.com/watch?v=Dwdr0Oo7YUE
However, XIII-2 improved on Serah's character by fleshing her out. She did mature.
XIII-2 spoilers below.
This is where we got to see Serah more closely. At first, she did come across as a little naive, but she grew strong very quickly and matured into a positively beautiful young woman. She was determined, passionate about her cause, willing to sacrifice herself for others, unafraid. Midway through the tale, she began to remind me of Yuna and the likeness grew. Like Yuna, Serah sacrifices herself for the common good. Despite the odds (she could die), she strives to change the future. She is willing to die if it means saving others and bringing them peace.
Her strength in the face of adversity is very similar to Yuna's. You can sense that both are a little afraid, yes, but find strength in their friends and their love.
Her strength in the face of adversity is very similar to Yuna's. You can sense that both are a little afraid, yes, but find strength in their friends and their love.