I think Bradley is the best athlete of them but I favor Alexander as a total package, think he's stronger and suspect he's significantly more durable. Khan in third to me, for now.
Alexander is good and talented but I think ppl are jus getting a slight bit over excited about this guy he is over-rated at the moment and tim bradley is under-rated. I like Alexander he's a skilled fighter but I wud wanna see him fight someone that is in the top 5 or top 10 at least and not a old version of witter or a limited but strong urango. Apart from these two questionable opponents he hasnt really fought anyone. He has all the potential but I wouldn't rate him the best 140lbs at the moment. We just need to wait and see how he performs against an A rated 140lbs fighter.
Overall skills and potentially: Alexander The man @ 140 currently: Bradley Not sure where really to put Khan but he's a good fighter nonetheless.
Alexander was loosing to Urango on one judges scorecard and another judge had it a draw (source is ring.com). I gave Urango 3 rounds as well and he was coming on and catching devon enough. Of course people forget all this and just remember the sweet ko. He did prove that he has a decent chin atleast among other things.