I finally started in on FLESH & BLOOD. 
Anyone curious about what this Drama CD-series is about, can take a look in the Listening Practice-thread.
The first CD release does a good job setting up the story. You get a good feel for the characters and what type of drama to expect. I find this to be very easy on the ears, much like a good TV drama. 
They’ve done a great job transposing the light novel to a sound only drama. Even when there is action, it’s easy to imagine what’s going on.
I guess, I’d rate this as intermediate level difficulty for now. 
(though I think it might get harder later on)