I review books on YA Highway and I find it particularly difficult 1) because, as a writer, I want to be respectful to other writers and 2) the YA community is small (go ahead, ask me who I've talked to recently.
). I thought about making it my policy to only review books I liked (which is my policy on Goodreads) but now I try to think of it as more like "promoting" books than reviewing them. Mentioning the parts I liked and thinking about what kind of reader might enjoy the story. Not that I'm dishonest - I do mention if I think the pace is too slow or the characters aren't likable (or, on the flipside, too perfect), etc.
Granted, I'm not a pro. But we do have lots of followers on YA Highway and I know YA authors read it. Take it for what you will.