Ever since I have embarked on a mission to migrate users of pirated Windows OS to Linux, one of the most common roadblocks I have encountered were from the College of Architecture. Whilst some of their computers in their laboratories have licensed copies of autocad, there seems to be a lack of available FOSS alternative on Linux. I am sure that you know of an architect who swears by AutoCAD but what if – what if s/he wants to migrate to Linux? What options does s/he have?
Chen Nan Yang of Linux.com gives us an insight on FOSS alternatives for architects. He concludes, however, "(T)he bottom line is that open source software such as Blender, QCad, Inkscape, and the GIMP can do just about any architectural drawing that commercial software can do, though sometimes they are less efficient and not compatible to your previous work (as in QCad's lack of support for DWG files)."
I'd say, "Good enough!" If there are more architects using these tools, developers will continue to improve 'em. Who knows? They might just surprise you one of these days.