I've heard only parts of the audiodrama CDs and from what I've heard, they are great. The same was with the CD dramas of the Left Behind Series. They were so good also. Better than the movies.(Left Behind not Narnia).
No the animated version wasn't the best film I had ever seen either, but it was Narnia and it was better, in my opinion, than the BBC version. Yet I did enjoy BBC's Prince Caspian and Voyage of the Dawn Treader very much.