I have previously paid fulsome tribute to Evelyn Waugh on here and elsewhere. At the time I noted the forthcoming publication of another biography, which has since appeared and I have since read: Philip Eade, Evelyn Waugh: a Life Revisited.
I have read it, and after doing so found my judgment unaltered: Douglas Lane Patey's 1998 The Life of Evelyn Waugh: A Critical Biography is far, far and away the superior--indeed superlative--biography of Waugh. Patey's book is not only a scholarly analysis of Waugh's life and work, but it is the most theologically informed and intelligent biography every written of Waugh. Indeed, I would say that it's very high and elegant theological literacy sets the standard for other biographies of Christian writers.
Eade's book, by contrast, pays scant attention to theology, and overall breaks very little new ground. His groundbreaking is extremely workmanlike, without great flourish or insight. So there is nothing wrong, per se, with the book--only that it is superfluous. What few new letters he has purportedly seen he manages, strangely, to render in a very flat and bloodless way, leaving the book teetering on the one social sin Waugh himself regarded as unforgivable: to be a bore.