"I write book reviews on a regular basis as a professional matter"

I was US Reviews Editor for the highly regarded webzine Infinity Plus for quite a while, so I think I understand the issue from both sides.

Oddly, in the case of one author who completed bitterly about the unflattering review I'd given his latest, we later found he was using my review as an example of how reviews should be written: he still disagreed vehemently with my conclusions, but felt the ways that I'd reached them, and my explication thereof, were exemplary.