HHG is a radio broadcast classic and so are the books and I'm not adding another comment about the content because I don't have anything new to add to the discussion.
HHG was among the first titles I got on Audible when I joined about 10 years ago. Recently, Audible offered a dramamtized version as one of their Daily Deals and I decided to get that as well. That said, my comments refer only to that dramatized version--and not the hard/softcover version whose picture is shown here. .
I didn't like this dramatized version for technical reason. I had trouble hearing what was being said in to many places. Sometimes it was the quality of the recording and other times it was that the actors were mumbling.
I did, however, thoroughly enjoy the 'making of HHG' narration that filled out the rest of the listen. That was very interesting and enlightening.