What do you mean? In terms of high damage? Windsong everyday. But you have to understand this, Windsong is only able to have such an absurd damage output due to the mechanic of her ultimate which is mostly only feasible is raids. What you are doing with her, is essentially relegating her role as a DPS, as a sub-DPM for a majority of the fight so that you can stack up her ST incantations till they are 3 star and you have a considerable no. of them and have her launch it all at once. This type of playstyle is not really feasible in harder content where rounds are less and your opposition gets stronger each your round. Jiu and Lucy are overall better because they are able to put out consistent high damage so they are feasible in all sorts of content. So, if you were to choose between them, Lucy would be the obvious choice.