Documentation
Don't let you scare away by the lack of documentation. Riot is based upon a stack of other well documented open source projects. If you are familiar with these technologies (mainly Hibernate and Spring), you'll notice that the extra layer added by Riot is actually quite thin.
Yet the online manual is very brief. The main reason is that Riot is a rather quickly moving target. Instead of having an (out-of-date) online manual, we try to provide as much pushbutton documentation as possible.
Besides the compulsive JavaDocs, Riot provides beandoc and fmdoc documentation. The latter tool has been purpose-built for Riot to document the various FreeMarker macros and functions.
If you are new to Riot, the riot-skeleton probably provides the most helpful documentation.