Katara is definitely one of my most beloved animated heroines, and most favorite Avatar characters. I would say Zuko is my second-fave, and Princess Yue as third.
My Favorite Aspect:
How the robe fits and fabric choices.
....and my necklace pendant. =)
Least Favorite Part:
The damn wig.
Easiest Part:
The pendant..ironically.
Hardest Part:
Nothing was necessarily hard, though customizing the fit (because I'm pretty tiny) was a bit daunting at times.