I have done this several times on my blog. Books that just don't work for me. I know my reading style pretty well, and I can tell whether I will like the book or not accurately about 80-90% of the time. If I finish a book, then there are aspects of that book that I enjoyed. I never talk about the author in a negative way, I only say what doesn't work for me. Normally if I finish a book, I give it at least 3 stars, meaning that I liked it. For these, it just wasn't a good fit for my stylistically, but since these were sent from the publisher, I decided to give it a try.
All of these books will be or have already been offered for giveaway in hopes of finding a reader that will love them and hopefully review them.
Karen at For What It's Worth and Mary at The Book Swarm occasionally post twitter-style reviews. Karen calls hers Short and Tweet, and I am going to borrow that review style here.
That isn't to say that the writing is poor or the characters are poorly constructed, it's personal on my end.