It's one of my favourite book series (there's a great thread on here from a few days ago about other books/series you might enjoy if you like this sequence), but I almost didn't listen as I also found the actor playing Will very stagey and some of the lines they made him say clunky and anachronistic for the time the story was set.
I know they evidently went for an actor who was the same chronological age as Will in the story, but the point is that Will is VERY old for his actual age...so although I enjoyed the sound effects and the atmosphere I also wasn't a huge fan of much of the casting. As well as that, the binaural element irritated me immensely the first time we tried to listen to it as a family unit. So yes, 6/10 seems fair.