Speaking about CADs withoug knowing what you want to actually do is quite pointless...
There are CADs for electronics, architecture, mechanics etc...
Sine I've been working with some professional CAD/CAM systems such as SolidWorks, MasterCAM, AutoCAD (I don't like it, but I thought I just name it) and some more, which I can't remember by names (all related to metalworking), I can tell you:
There simply are no usable CADs in this field on FreeBSD, I tried many (if not all in
cad/), Even for 2D designing....
(qcad sux)
However there are some nice CADs for electronics
(Haven't used much, didn't have time to learn, but they looked very promising)
Switching from metalworking to IT is what let me switch to Linux and later FreeBSD from Windows....