I don't have much experience with HSB, but I used Cadwork at my old job and now own a copy of Dietrichs (and am very happy with the switch).
The main draw I see towards HSB would be the familiarity with the AutoCAD environment, which most of us know quite well. However, Dietrich's is so easy to become productive quickly on (just hours for standard style frames) that it doesn't really matter. I am constantly wishing their were more Dietrich's style commands in options in AutoCAD when I have to go back and use it now.
I would think sticking to a software written specifically for timber construction by those in the industry would be the way to go (HSB seems to be the Swiss Army Knife approach?)
Joe