Yes, corporate personhood is constistent with the U.S. constitution, because it allows people to exercise free speech. Corporate personhood is allowing all of the people who make up the corporation to exercise their free speech, together. To limit the corporation would be to limit all of the people involved from speaking their mind.
Corporate personhood is not consistent with the United States constitution. Individual rights and liberties are paramount in our nation's founding document and no mention of corporations is made in the constitution. In order for corporations to achieve legal personhood, an amendment to the constitution will have to be made if Congress doesn't make laws supporting such a measure first.