Probably Solo. He's legendary, whereas I never got the impression that Mal was. As far as characters and characterizations go? Mal all the way. I love Han and Harrison Ford, but Mal and Fillion are truly badass.
I'm glad you did, because I'm retarded. Solo was reputed to have been among the fastest draws in the galaxy, but Mal held his own against the Operative. Solo wins the gun fight, but gets utterly annihilated in a fist fight or martial arts duel.
The lead character from Joss Whedon's early 2000s attempt at a sci-fi TV show Firefly, portrayed by Nathan Fillion. He's clearly based off of Solo, except Reynolds is a true rogue; he's a smuggler but he kills without hesitation. He's a lot more interesting, imho.