I suspect that T5 has branch endings:
1st-Hwoarang beats Jin in the Tournament but Jin decides not to pursue the matter, stating he needs to "fulfill the destiny of his cursed blood" (which roughly translates into I got my ass handed back to me. In style). I suspect that being a self-centered jackass, Hwoarang dropped out of the tournament thereafter and maybe Jin won by default.
2nd-Jin defeats Jinpachi and takes command of the Mishima Zaibatsu from his grandfather Jinpachi, indicating that he may follow in his father's (Kazuya's) footsteps, including embracing his Devil Gene
3rd-Devil Jin defeats Jinpachi and absorbs his power to become True Devil or something or other.
I suspect that Hwoarang's ending may have been canon since Hwoarang is seen putting the boots to Devil Jin in the 2nd Tekken 6 trailer back in E3, possibly for payback (In Hwoarang's ending, Devil Jin attacks Hwoarang and blows up his bike. The fight thereafter is left to imagination) but like Sloth7d said, only T6 can confirm this
But in terms of gameplay (as a 2 time runner-up in my local Arcade tournaments) between the two characters Jin has the definite edge over Hwoarang for two reasons:
a) He has only one stance
b)He can parry
Hwoarang has the advantage of speed and range however to deal his heavier damage you need to get him into one of his 5 stances: Left foot forward (his original stance), right foot forward, left flamingo, right flamingo and...Disrespect (useless, trust me). The key to playing Hwoarang is to go Trickster on an opponent. He's not Baek, he cant keep barraging a guy with seemingly endless kicks that go high and low. The flamingo stances keeps your opponents on edge, 50% of the time when they see you switch to a Flamingo stance their first reaction is to block low. From Flamingo you're going to need to make some split second decisions if you want to branch for major damage. Jin doesn't have that problem. With only about 64 moves which consists mostly of some serious combos (Savage Sword ***Scrubber's Choice), a Jin player doesn't really need to concern himself with style or tricking. He has some really easy fakies and some fast combo-breakers that will leave you open. Worse still, Hwoarang players tend to go all-out with a serious offensive. Jin's parrying takes care of that. One kick parried and its Electric Wind God Fist which will send you flying.
