Not their personality (or why not), but their professionality, always showing up. Porter comes to mind or Postol: never great but always very good. Neither's on my fan list but I respect and admire both.
Speaking of Porter, Danny Garcia comes to mind. Can“t stand him and I have serious disdain for his dad, but the kid is always 100% ready. No excuses.
Chisora. Fights anyone and fears no one. Lots of losses but cannot ever say he ducks anyone. Bigger heart than most. Also sets a fine line for those who could make it and those who cannot. He's better than average, but not quite good enough to make the top 10. I think he's a good servant to heavyweight boxing.
Porter as in Shawn Porter? Yeah, that's a very good pick, always in shape and rarely beaten clean - not that he's robbed, just that he's almost always there or thereabouts.