Since everyone else is only commenting on the positives, I'll make my review a little more pessimistic.
The art is underwhelming. It begins rather slowly (not unbearably slow), but really picks up after the first volume if you give it the time. The mangaka shoves a lot of gore into your face in the first few volumes but there is little to be found in some of the later ones.
I'm not sure why there are remarks the originality of the main character. He is far from the first character to ever use brains over brawn, especially with the recent popularity of characters like Lelouch and Yagami. The mangaka himself even constantly makes comparisons between Eumenes and Odysseus; however, unlike Lelouch, Light, Odysseus, or almost any other main character in a popular work of literature you can think of, Eumenes is flawless.
He isn't weak, short-tempered, arrogant, boring, antisocial, evil, bad with girls, or even too kind. The story is basically about what the perfect male specimen would do under the most unfortunate conditions possible, but no one seems to have a problem with this because it's almost impossible to dislike him.
Definitely one of the better mangas out, but far from the best.