I'm using version 0.19. Get it from github.com/FreeCAD/FreeCAD. I've found freecad to be as powerful as the costy packages out there, and it's open source. You can compile it (I have) and you can add in plugins as well. I gave it a 4 out of 5 for ease because it's too powerful to be easy, although the tutorials on youtube really go far in smoothing the learning curve. I've designed very complex gear systems after only a couple of days of playing. I now design things, export to stl files, and then 3d printed them. Such freedom!