Book reader community.
That's a good question. In the past I've used r/books and seen what people recommend, though I'm now trying to avoid Reddit where possible. I think Goodreads can be a valid resource, but instead of relying on the overall review score you could find particular reviewers that give well thought out reviews and follow them.
That said, why not post something here to get the fediverse's opinion on a particular book?
I find reviews of books on Goodreads to be open and honest especially by users. I’m a frequent poster of reviews on books that I have read and try to be honest about them. If your really stuck you could always ask ChatGPT..!!
I use Goodreads mostly but I will agree the reviews are mostly miss so I use it primarily for tracking
I know this is a late reply but I read them on TheStoryGraph.