I think this is great as it accompanies a great general book for FCE. It has good practice exercises for listening in the book and you can't do those without the audio so it's a catch 22 really. You have to buy it.
I buy a lot of books and wonder whether to invest in the audio as it is usually very expensive. It is well worth it though as it enhances the lesson and the students get to hear different accents and speed of speech etc. Very happy I bought it.