In order to answer this question, we must first define what a "hero" is. For me, a hero is someone who performs altruistically. He is looking out for the betterment of others before himself. If this is the deciding factor, I would have to give it to Dutch.
In Predator, when it turns out that it wasn't a rescue mission, it is clear that Dutch is unhappy. He doesn't view himself as a mindless killer - he and his team go in to rescue those who need help. Throughout the movie, Dutch is completely focused on the survival of his team. He offers HIMSELF as bait for the trap, kicks a gun out from Anna's hands so the Pred doesn't focus on her, and we all know "GET TO THA CHOPPA!"
Harrigan, on the other hand, is out for Revenge. At the beginning of the film, while the Predator is only hunting down the scum of the city, Harrigan and his crew joke about giving it a job. After Danny is killed, Harrigan doesn't care about anything other than revenge. He does not care who gets hurt in the process. He does encourage the others to back off from the chase, but it was not because he was worried about them, it was because this was HIS fight, and HE wanted to make the Predator pay.
So, while both are Badass, I definitely see Dutch as a true hero, while Harrigan was more on a vendetta.