There are pros an cons to both. Brushing the coloring liquid on will give you the freedom of customizing and blending colors along with the adding pink tissue color. It is harder to teach how to brush and you may get different results with different people brushing. The speed of brushing also the size of brush will effect the end color. Also brushing will limit the penetration of the color leaving white spots if you need to adjust post sinter .
With the dipping technique it is easier to teach therefore you will get more consistent shades along with greater color penetration. The ability to add modifier liquid (like incisal enhancer from B&D Origin) before dipping into the color will allow good incisal blend without too high of value.
If you have one person coloring brushing will work good but if you need to try to teach someone how you might be better off using the dipping technique.