It depends, since Noelle’s effectiveness is currently locked behind her constellations.
At C0/no constellation, Noelle is pretty much a sub-par character, since her healing is still chance-based, and not always heals your party (at lv10 skill, the chance is at 59%, which is kinda meh). Her first constellation bonus will solved this, since it increases the healing chance to 100%.
Meanwhile, her full potential is locked at C6/last constellation bonus, which is her best talent that totally changes the character, where her burst now adds 50% of her DEF as bonus ATK, and on top of longer burst duration everytime you defeat an enemy.
So yeah, if you wanted to use Noelle, you pretty much need at least her first constellation, which will increase the healing chance to 100%. If not, then Barbara is much better in terms of healing.