There are some features not included with the current beta but are available if you download from source.
This is a plugin that I wrote that allows TeamCity to work with FluentBuild. TeamCity plugins are written in Java and I am not a Java developer but it seems to work quite well in my environment(s) so far but I am still not 100% confident to officially release it.
For my testing I was converting peoples NAnt scripts by hand and it started to get pretty tedious. I decided to create a really quick and dirty converter application. The application works fairly well to get the initial conversion from nant to FB. It will create your variables (and attempting to determine if they are BuildFolders or BuildArtifacts), initialize them, and create methods for each build target that you had. It does not parse build targets and convert them to FB syntax yet though.
I always found reading output on the command line was a pain so I started working on a UI component to run builds. It is in its very early stages but it is much nicer than using most command line applications I hope.
Where these features will go, I am not sure but if you want to play around with them then feel free.