First I heard of "Domino UI"

First I heard of "Domino UI".

Any one out there with experience with it?

regarding UI there is now good libs for GWT if you are looking for material design: for example

Domino-ui : type safe UI libs based on elemental2 and elemento with material design and has no dependency on external JS.

Vue-Gwt :  GWT wrapper over Vue.js

both are targeting GWT 3.0