The vast majority of books are done full script these days, but there are exceptions. Everything Dan Slott writes is done Marvel style (he just did his very first full script for a secret project recently), and Al Ewing has been doing his Marvel work Marvel style as well. Matt Fraction’s played around with it as well, and has evolved a sort of hybrid style that’s somewhere in the middle that he’ll use when the occasion warrants. And there are likely others whom I’m forgetting.