Lorrie Moore, on Updike:

And his nonfiction! Even when his essays included a harsh criticism, he politely coiled it, tucked it inside, part snake, part rose, and the reader would feel the bite sprung silkily only at the end — in a balletic allegiance to both generosity and candor. Self-knowledge and self-forgiveness bestowed their own empiricism: he knew too what it was to create weak art.

Moore's Self-Help, by the way, is great.