Carth's manliness: Near zero, he whines, bitches and whines some more. Also, he has tendency to flee when seeing Sith Lords.
Malak's manliness: Closet homosexual. Anyone who is comfortable running around in full body-spandex just oozes homo-eroticism.
Atton Rand's manliness. Still unclear. But apparantly he's done a facejob after being picked on at last E3, which isn't exactly helping him getting any manliness-points.
...so that leaves Atton Rand as the winner, since he doesn't have a fetish for spandex and he hasn't shown signs of cowardice either. You go Atton!