Noble Six is the protagonist of Halo: Reach, and makes the story very rich. He is a man with few words, but we all knew his intent... to save reach. He fought to his last breath, given the option to escape, and didn't even back down to his certain death just to kill any and every last elite. He fought the fight he couldn't win, and showed his courage, and personality.
Noble Six was a character I could connect to, even with such few roles.
That being said, the Master Chief, while you can bring up the same points, I never really connected with.
He feels so dry, too quiet, and just too powerful.
In Halo:Reach, when the Elite overpowers you to when Noble Six is stabbed by the elite, he is not just an action hero you can find in a boring movie, but rather, a soldier that is actually in danger.
Noble Six > Master Chief