Excellent review, couldn't have done so myself.
Gungrave is indeed one of the best anime's ever created, not just the art, but because of the underlying morals and facts/flaws about humanity that they incorporated into the anime. It definitely shows us just how wonderful and devastating humanity can be at its finest and at its worst.
Excellent plot, characters that leave lasting impressions to the audience, all in all the best combination if I may say so myself.