Christie behaves more or less like an organized criminal or if you want use a less harsh term, a bully. He, as well as Scott Walker, are the most perniscious corporate thugs that run for POTUS.I do enjoy seeing those "limited government/states rights" Republicans make threats like that though.
I wouldn't classify Christie as a "limited government" Republican. Someone who does tyrannical things like creating a traffic jam because someone refused to endorse him (which I understand he denies) isn't going to fit that description. Claiming that you would push illegalizing all use of marijuana, at the federal level, does not support that claim either.
Trump is basically just a variant of Berlusconi whereas Bush is fairly oldschool in terms of having at least some statesman-ish behaviour.