It is pretty much fully featured as what you would need in any typical web-app.

One crucial thing that is missing is guaranteed browser support. That is why we only used it for the clients internal frontend. But as I understand it, this will be addressed in the upcoming 5.0 release.

Also the resulting HTML is not always as optimal as I would hope.

All in all development is just so much faster and cleaner. No need to worry about layout and style. After using style-elements for a while, HTML + CSS seem like a really stupid idea to describe layout and style.