According to this paper from 2017 (Instance Normalization: The Missing Ingredient for Fast Stylization), Instance Normalization helps improve the qualitative output of style transfer.
Thankfully, tfjs seems to work well with the webgl backend 🎉.
Notebook is here: stilva/adain-notebook
Below is a set of faces with style transfer applied to it with Instance normalization. Hover to see without Instance Normalization