I agree that this section is an extremely powerful part of the book, one that makes the novel as a whole absolutely unforgettable.  All the characters seemed very realistic, with the exception of (for me) the doctor who tended Didier's broken leg.  Perhaps it was a case of him seeing too much death and destruction, but he really seemed overly callous in his treatment, and was more concerned about his missed hours of sleep. 

Captain Renouart - makes no choice.  Here was one of the few occasions in the book where a man stands up for his beliefs, for common human decency, and refuses to choose a man to be condemned to death.  Although his final draft of a reply to Dax is less critical of the order than the one he originally planned to send, it nonetheless gets his point across.  Pity he couldn't send the first one, and perhaps discretion is the better part of valour when he evades any follow-up to his refusal by going for a ride.  I like the fact that Cobb does not take the easy way out by making his characters 100% good or evil.

Lieutenant Roget - chooses Didier.  What a fine opportunity presents itself, to be rid of the one man who can cause him problems, and to twist his selfish motives into something completely selfless and dutiful.  I get the feeling that even though he needs Dutch courage to follow this path, that he would probably have made the same decision even if he were sober.  Roget is quite easily one of the weakest characters in the book, with little, if any, integrity.

Captain Sancy - chooses Ferol.  A man who likes playing God, and feels that he is ridding society of a less-desirable.  He actually relishes the chance to exercise his intellectual faculties.  He is so far removed from humanity that he finds it simple to tot up the pros and cons of each person he considers for death.  Out of the 4 commanders, this is the one I equate the most with evil, and is very frightening to contemplate on a larger scale.

Sergeant-Major Jonnart - chooses Langlois.  On the face of it, this seems to be the fairest method to select the condemned man.  At least he is upfront with the men, and explains what is happening as far as he knows it.  This method removes the blame from himself to sheer chance, but even then he bungles it because of an ambiguous number, and so he is forced to make the decision which frees one man, and condemns another.

The different ways the men faced their deaths was so well-written, and brought tears to my eyes.  To face the ultimate penalty even though you are completely innocent, and in fact did the best you could, is so contrary to peacetime justice.  No innocent until proven guilty here.