Trump may be an asshole, but he's not hardline tea party, and has never caused a government shutdown - Cruz was instrumental in the 2013 one.
Cruz has agreed with all Trumps statements about hispanics, women, and muslims, so in that regard he's at least as bad as Trump.
Trump doesn't like gay marriage but since the Supreme Court has ruled on it, he's content to let it be. Cruz wants to pass a one-man-one-woman amendment to the Constitution.
Trump wants to open relations with Cuba, Cruz vehemently against.
Trump wants to raise taxes on the wealthy, and lower them on the middle class. Cruz follows party line that taxes bad.
Trump is okay with limited gun control, Cruz is against even background checks.
Trump wants single payer, Cruz wants to repeal Obamacare.
So if I had to choose, it's going to be Trump every single time. Hell, I'd pick him over Clinton too.