[tlamponi]

Your CAD experience level sounds like it is similar, but a bit higher than mine (2 years hand drawing, 2 years CAD, some more hobbyistic CAD & 3D modelling over the years for personal projects), so yeah SweetHome3D might not be that much help for you over using some CAD software directly.

I found furniture handling OK, but certainly has its rough edges. Good thing is that one can just import 3d models and so create the relevant pieces of furniture themselves; or use the generic boxes that SH3D has, if it's just for 2d space usage.

I did a few office space modellings with it, i.e. to get a feeling of how the space could be used best, and for that I found it quite OK. The result I got compared to the time invested was pretty good for my taste.