A parametric modeler
Why using OpenSCAD ?
OpenSCAD is a very specific tool in the CAD world.
I had some difficulties at the beginning as it is a Functional language, but I finally get used to, and after building my own library, I can do developpement relatively quickly compared to an interactive modeller.
I had some practice of Draftsight (2D AutoCAD clone) and Sketchup, unfortunately Sketchup is not a good tool for 3D printing, for multiples reasons (The STL files are not smoothed and have a lot of defaults).
The biggest default of OpenSCAD is that you cannot export your models. It is only possible yet to export part by part in STL format. That means you are locked with the program.
What version to use
One important development is a new GUI for parameters to interactively modify parameters with widgets and also create data sets, in a similar way as is done by the Thingiverse customizer. First 'official' release was in development snapshot of 20 January 2017. As of May 2017, this extension is still buggy particularly with included files, but usable. As all development functionalities, it needs to be specifically activated, see the OpenSCAD manual. Next version of my Delta simulator will use customizer datasets instead of including data files.
I yet developped in OpensCAD:
There are also smaller project, you can find all my Openscad Work on Github
I also done some other undisclosed projects...