Personally I loved the trilogy. The graphics were just amazing

FFXIII was my least favorite of the trilogy but it introduced us to the group so it holds the most nostalgia to me.
My favorite was FF XIII-2. Serah was just so emotional and I really grew to like her. noel was a really good counterpart to serah, he wasn't overly macho but was strong enough to carry the story as the main male hero.
I really liked FF XIII: Lightning Returns too. I put most of my time into that game and even replayed it twice. The customization of weapons and outfits was great and I loved exploring all the different lands.
overall I thought it was a really enjoyable saga of the FF franchise.
