Clinton has always had an issue with coming off as insincere mostly because she's been in the public eye so long and so frequently, plus she has a odd record in certain areas. Can't say i'm terribly excited for her, but ya know obviously better than the alternatives. But on the other hand she definitely buttoned up, and highly qualified for the position.
Trump is extremely charismatic for a certain audience and has managed to hold media attention and brush off consequence for his actions and words fairly easily, he is perhaps the most skilled manipulator of news media ever seen, and everything he does contributes to the perception of strength he has created. Anyone who thinks he isn't intelligent is fooling themselves, highly impulsive yes, but very intelligent. This election will not be the landslide victory for Hilary some on this forum think it will. With that said not much of a chance of him winning the election, but discounting the possibility tis questionable.
Bernie Sanders is your World Philosophies 101 teacher, peddling half formed ideas and hope. Both of those are of course deeply toxic.