I have been reading Klein's intermediate series and this one really stands out, in my opinion. It is significantly harder from the first three, contains a lot more idiomatic expressions than them and the story is fairly engaging. I wouldn't say it is a good Krimi but quite fun nonetheless. One could say the author really enjoyed taking a free hit on vegans.
I loved the fact that Grabowski is just extra naughty in this one. He is the Vince Masuka of die Mordkommission.