I also support dual licensing the projects. It allows companies to release reasonably good part of their product in public domain, while still catering the needs of enterprise clients. Mostly they also release some part of awesome enterprise features in gradual timeframes. we can fork and release community versions according to our needs(respecting IP and trademarks of company). We can also contribute upstream changes by dual licensing our contributed code with GPL and to their proprietary contributor license.

My favorite projects following this route are Redhat/CentOS, MySql/MariaDB and Virtualbox.