I prefer reading book reviews over book reports. So often, reviewers tell me everything about the book, but not whether it's a good read, well-written or anything like that. Ideally, a book review should be 10 percent report, 90 percent review.
Anyone can write a book report, but a writer needs to carefully consider the work in order to do a well-written review. I've been guilty of giving too much plot in my book reviews, and I've had to revise them as a result. I find that stepping away from something like that for a while and going back to it helps me focus on what I need to change.