I assure you I know a bit more about them than what they write
in "Lost Victories" and "Panzer Leader". 
Fact is, these guys were among the best generals Germany had during
the war. Think about it, imagine if Hitler didn't meddle, replaced
idiot Keitel with Manstein, the world might well have turned out
differently. Or at least the Allies would've taken a lot longer to
reach Berlin.
As for their autobiographies, sure they might've exaggerated a bit
here and there, but most objective histories of WW2, written by
British and American authors (their enemies) give them full credit
for Germany's early blitzkrieg (1939-41) victories.
And Guderian WAS the father of the armored force. Even Patton gives
him credit for his innovative ideas.