Your writing voice is the deepest possible reflection of who you are. The job of your voice is not to seduce or flatter or make well-shaped sentences. In your voice, your readers should be able to hear the contents of your mind, your heart, your soul.
Nowadays, I only review books I really like. It's cowardly, I know, but I figure it's not my job to make people unhappy. I'll leave that to the professionals.