I bought the "non-special edition" a few years back, ripped it myself and it sounded great. I can't find my digital versions, so I bought the special edition, regardless of the other negative comments. DO NOT IGNORE THESE COMMENTS!!! This is a horrible version. The sound mix is bad. It really does sound like the guys were in different rooms.
Please, I beg you, do not get this one. If you can find the "non-special edition" get that one. Or, buy the CDs and rip it yourself.
If you are new to Douglas Adams's work, this is not where you should start yoir journey and you are better off with the audiobook version.
If you are a Hitchhiker's fan than this dramatised version is a great way to enjoy the humor.
The biggest downside of this recording are the sound effects; though they do contribute to the story telling, sometimes they are so loud that you can not hear the dialogue