I think it's especially important for an editor to say what he's enjoying. For a novelist to be told, midstream, what he's doing right can actually influence the unwritten parts of a novel in a positive way - praise helps a writer know what's good about what he's written, what's interesting and exciting, and what to work for in writing the conclusion.
Donna TarttShe closed her eyes, dark-lidded, dark shadows beneath them; she really was older, not the glancing-eyed girl I had fallen in love with but no less beautiful for that; beautiful now in a way that less excited my senses than tore at my very heart.
Donna TarttEven if you need, and want, a second opinion, it can be dangerous to have people telling you what they think you ought to add, or cut, before you've even finished telling your story. One loses heart; one loses energy and interest. Or at least I do.
Donna Tartt