I've read three books recently that didn't use those "I am a famous person so you should care what I think" blurbs.
The back cover of Sidekicks used three quotes from professional reviews (and one from Jeff Kinney who is, okay, a famous person), all relating to the author, Jack D. Ferraiolo's, first book. The back cover of The Romeo and Juliet Code also used quotes from professional reviews relating to an earlier book by the author. What these kinds of quotes tell me, a reader, is that people who critique writing professionally have read these authors' work in the past, and here is what they think of it. Whereas the quotes from private individuals may be from friends of the author or from writers who were asked to blurb and felt they had to do it. And, in my experience, such blurbs are often way over the top and gushy, or witty rather than accurate. Whereas people who are paid to review may still be wrong in their assessment of an author's skill, their professional work is being quoted. They aren't doing anybody any favors by blurbing so we readers can hope that they're calling it as they see it. I find this kind of quote far more accurate and far more enticing.
My favorite back cover, though, is still Dust City's. No quotes from anyone. Instead, you just see the line "WHEN YOUR DAD IS THE WOLF WHO KILLED LITTLE RED RIDING HOOD LIFE IS NO FAIRYTALE." It's hard not to pick up that book after seeing that.