Surprisingly not much has been written here about alternative software for AutoCAD.
I am architect and early on I was searching for other lower cost options for AutoCAD
because we didn´t want to update our licenses for expensive money all the time.
Then we came across ProgeCAD PRO, which now replaces AutoCAD in our daily work
Have a look here: http://www.ark-ow.com/progecad.html
you get it for 10% of the price of an AutoCAD license.
Last year we planned an elderly people home with 3000 m2 gross area, we used
ProgeCAD to do working and detail drawings in conjunction with other ingenieurs which
used AutoCAD, no compatibility problems occurred.
We have been experimenting for some years now how to get dxf drawings into Blender and
we had found work arounds with external 3D converters which translated 3ds or dxf files
into Lightwave format *.lwo files. With the newest version of the dxf importer script byEd Blake
and Remigiusz Fiedler this is now obsolete.
To import to Blender directly, just choose all solids with the filter command and explode them
then save the file as AutoCAD release 11/12 ASCII (dxf) and import it with the up mentioned
dxf importer into Blender.
Make sure that you don´t work in millimater units but meterunits.