I'm certainly not an expert nor anyone whose opinion is of any value, but I do like him much more than the other cock. This one looks meatier, which, to me, is how Marans should look. They say white fluff at the base of tail isn't a good thing if that's white fluff I'm seeing. They say it isn't supposed to be seen in this variety. The French web page says, "... white feathers are to be banned of the body." [Those are the exact words from the official website.] His tail looks higher than 45 degrees, but that may be the wind blowing the feathers up that way. The tail angle is something that good breeding will fix in his youngsters. I'd give him a solid good for general overall body shape and the rest of his coloring (minus the white fluff if that's white fluff). Of course, you'll want to look at him from the top down and see a good amount of width across his shoulders, too.
His wing feathers look a little ragged, like maybe he's had a rough time of it and needs a few weeks of rest and recuperation. Of course, that's not a breeding issue.
Have you ever done an image only search on the web? You will get all sorts of pics that way and will get a feel for what is a really good looking male because almost every breeder will post their very best boys.
Anyway, that's about the best I can do. Hopefully some more folks will chime in or maybe you could repost in the thread titled "Marans Thread - breed discussion and pictures are welcome!"
Edited. Changed word breed to variety and added direct quote from official French website as of Nov 10 2010.