Reasons to avoid Trump like the plague?
1. No political experience. A new convert can't be pope his first year. Trump's financial behavior has not always been successful, and in fact he's been through bankruptcy and openly admits manipulating bankruptcy laws to enrich himself at the expense of society and other people, so that he protects himself from risk by getting governments and banks to shoulder more of the burden and let him off the hook more cheaply -- lack of adequate responsibility, coupled with repeated failures on a large scale, plus actual broad lack of experience on Wall Street and with stocks, adds up to undermine his reputation as bringing good financial experience and expertise to the presidency.
2. No specific solutions for our problems, just meaningless rhetoric. He is impulsive and more interested in self-promotion than necessarily accomplishing significant goals -- even his finances are geared heavily toward promoting his personal brand and making him more money in order to further self-promote, with much of his behavior in public seeming largely motivated by garnering attention.
3. His business practices have ridden way to close to the ethical/legal edge for me to have much confidence in him. Trump has been repeatedly accused of being untrustworthy, by investors and buyers as well as others, and some of the accusations include allegations of fraud -- lack of trust and concern about corruption are major problems for a presidential candidate.
5. No understanding of foreign policy issues. He surrounds himself with "yes men", so he doesn't have experience building a team designed for purposes other than promoting his own narrow agenda and providing information that might be in contrast to his own position and goals.
6. He is prone to embrace uninformed positions that turn into major embarrassments for him -- his promotion of the "Obama isn't a U.S. citizen" myth, his promotion of the anti-vaccination myths, and repeated comments that give the appearance (correct or not) that he doesn't check facts or stay informed about serious issues.