I mostly enjoy the Peter Grant books, but there were a few clunkers along the way for me. Aaronovitch has two proclivities that can drive me absolutely bonkers: 1) over-the-top acronym usage (yes, I realize it's a procedural, but still, I've no desire to keep a decoder cheat-sheet handy!); and 2) mind-numbing architectural dissertations. I just couldn't possibly care any less about what buildings/houses look like.
Other than that, it's all good!