Material UI provides Cloudcraft.co with a clean, professional looking and very easy to use set of UI components build with React. The few issues we've reported to the developers have been quickly fixed each time. I highly recommend using Material UI for both consumer and enterprise web apps. The styling system in particular is very nice to work with, and allows you to easily add your own brand's look and feel throughout the UI.

We like the pure simplicity of Google's Material UI. It is simply too much overhead today to design custom UI styles.

We use Semantic UI for our frotend. A heavily customised version of it, but still Semantic UI under the hood.

Used Semantic UI + Angular2 together with Spring or Node/Express for full stack web application development.

I'm using MUI to build out the admin portion of the site under Firebase authentication.

Martial UI is used by Admin-on-REST, the frontend used by Gofus.

We haven't yet, but we would like to integrate into our Web App.

Ambar UI is based on Material UI components

It's pretty. Used it once for MDST.

Grid, widgets, theming.