be all it's cracked up to be

not be all it's cracked up to be

if something is not all it's cracked up to be, it is not as good as people say it is Her latest book isn't all it's cracked up to be. I wouldn't bother reading it if I were you. It's a good restaurant, but it's not all it's cracked up to be.
See also: all, cracked, up