Cruz is the most conservative candidate. Trump’s record the last 20 years minus immigration is really close to Gulliani. They don’t like to talk about that though.
Trump has no record to disparage. He has never held office before.
One other item that seldom seems to come up in the discussion is the little incident in Atlantic City where Donald Trump used Eminent Domain to displace someone from their home in order to build a special parking area for limousines at one of his casino hotels. Using the power of the state for a wholly private benefit and not for the general public good, such as road, bridge, subway construction, etc. is an attack commercial in waiting and one that would resonate with most voters. The last genuine plutocrat elected president was FDR and he was able to get away with it by running as defender of the little man in the bread line. Can you imagine what the Democrats (and their foot soldiers in the media) are going to throw at Donald Trump in a general election campaign?