Best to keep in mind that unlike Churchill, whose politics were obvious, Schirer was a Communist enabler like Durranty.
He finally fell from the pinacle of American journalism by supporting the Soviets against the US during Trumans time.
And before he finally disapeared he equated the American military and President Nixon efforts in Vietnam to the Germans and Hitler.
Shirer's political bias is discussed here from time to time. There seems to be general agreement that his first-hand accounts of the events during this period are reliable. They are certainly interesting. You are welcome to comment on the excerpts if you notice them drifting away from objective reality. If my historical sources provoke a little controversy, with resulting discussion, so much the better.