Substance is a free (BSD) look and feel and comes with many skins and configuration options.
It is easy to install and configure. I used substance even for NetBeans in the past.
NEW online workshop: WebStandards Igniter (online)
Airport MUC workshops: Java EE 7: Bootstrap, Effective, Architectures, Web, React and Angular, Testing and Microservices
A book about rethinking Java EE Patterns