Is anyone in the GrabCAD community currently using open source CAD software?

FreeCAD is probably what you want as far as pure CAD goes. Blender 3D or Blender 2.6.3 is a very good tween package.

I use Solidworks but, a promising free CAD app is freecad

http://sourceforge.net/projects/free-cad/

There is also http://librecad.org/ it's only 2D though. A shop that I work with now uses that instead of AutoCAD.

I use FreeCAD.

Yes, I am using freecad on UBUNTU

I use blender for 3D, and draftsight for 2D. Both are great programs.

i install Linux Mint 16 Cinnamon 3 weeks ago(,because i used XP Pro,to old for Microsoft),and i try to use Freecad..

but from Solidworks,or Autocad job it's not easier..