I do find this sort of question, as seen here at Writers Unboxed, a little odd.
Of course you have a right to write reviews—we’re all readers! Readers get to have opinions!—but you should give some thought to what you want those reviews to accomplish. Do you want to boost other authors and recommend the books you loved? You can do that by writing positive reviews of the books you loved and just not writing about books that don’t fit into that category. If, on the other hand, you want the internet to reflect the complete record of everything you read and what you thought about it—positive or negative—go for it. But remember that some authors can’t help reading their reviews, and your name is going to be associated with that negative review.
The bolding is mine.
I think this is largely a no-brainer. There is absolutely no reason not to write positive reviews of books you love, whether or not you are an author. So why ask the question: Should authors review books? Yes. yes, if you are an author, you absolutely should review the books other people write.
You should write glowingly positive reviews that are also honest and perhaps mention something that might not work for just every possible reader. The author of the book will love that, or at least it’s hard to imagine otherwise. There’s no reason to hesitate. Onward!
So the actual question is: should authors write negative reviews of other people’s books? That’s a much harder question. I’ve only written negative reviews about three times.
Once, I utterly panned a book. I put that review only here on this blog. I did not feel it was necessary right to put a truly negative review on Goodreads or Amazon.
Wow, was that a terrible book. Looking back on it, just … wow.
I’ve put one fairly negative review on Goodreads and Amazon for one specific book, Control Point by Myke Cole, and I’ve left it there. I had very specific reactions to certain implausible plot points and I think those were fair. I did think the actual writing was fine and said so.
For Tana French’s In the Woods, I posted a review of the “Wow, this did not work for me at all, even though it is beautifully written” type.
I kind of think those may be the only negative reviews I’ve ever posted.
I think it’s not only tactically wise for an author to generally post positive reviews, but in general, I truly prefer writing reviews of books I love and posting those here and hopefully seeing you all comment about the same book.