I have spent some time now working with this project and I am really very impressed. This is the first open-source project I've used that is this complex. The code base is really very complete. There is nothing stopping me from customizing the app in any way that I want. And there are literally thousands of hours in this project. If this was a project for a medium sized corporation I would SWAG it at $350k plus for the initial release, and then you have at least one major update.
Don't get me wrong it has some rough edges, but so far I have not had a functionality failure. My only beef is with the way it displays and does some things. But all of those I can tweak how I want, and honestly other people might not want those changes. Documentation is kinda weak, but not bad and better than many projects I have been on. The rather funny part is I have not went back to the docs one time so far, the comments in the code have been all I needed. How many projects can you say that about?
Its a one or two minute download and free. Amazing.