I'm listening to the Star Wars Radio drama as well (Christmas Present), and it's an interesting take on the movie. However, I can't help but feel that it has some large issues. There is a rule in screenwriting that states that you should always start the scene as late as possible and end it as soon as possible, and it is remarkable how much faster the movie flows. Granted, they were trying to make the radio drama more of an episodic story, but so much that is added seems to have little point.

Take for example the scene where Luke and Obi-wan inspect the blasted Sandcrawler. In the original movie, the scene starts after they have discovered it, whereas in the drama, we travel with them on their trip to Anchorhead and have the scene described to us in a more drawn out fashion.

It just makes you appreciate how much information is packed into the visual channel of Star Wars, that they need so much more time to explain it all.