Tiki is the free and open source web application with the most built-in features. So whatever feature you can imagine running in your browser window, chances are Tiki does it.
Lacks available extensions or plugins, and extending functionality requires custom programming.
Management of content and data is relatively straight forward, but there may be a bit of a learning curve. Some programming experience may be required.
Has a larger active community. Support is always available for free or as a paid service. Excellent documentation available.