John I think it was Hemingway that got into this. First hand accounts are wonderful and insightful to a reader.We love the intimate feelings and drama associated therewith.
But Patton did not interview men in foxholes to decide how the war was going. He spoke with troops to find out matters like morale and attitudes. Very important but it requires a broad spectrum analysis for its efficacy.
Read the news and find out what the news thinks.
And you cannot even believe what you see in film clippage. I think it was an old time comedian who offered "who you gonna believe, me or your eyes?"
So no there are no "good" sources. Life is filled with one man or another's perspective.
The best we can do is gather as much as we can and with the filters and base opinions on, not consensus but contrast.