I have been looking into both OpenSCAD and OpenJSCad as an alternative to Inventor. I love the power of OpenJSCad and the low-level access to the CSG generated objects I have seen in the examples! You cannot get that kind of access to the resultant solid models with OpenSCAD.
With that said, I find that the OpenJSCad.org preview/editor site is a bit too toy-like for me. Everything covers up the model I am trying to discern. In contrast, the latest version of the OpenSCAD editor seems more polished and useable.