FWIW: I am not a great fan of two-column style because I read quite a lot directly on-screen and that's when two columns become a pain, particularly when you cannot fit a whole page on the screen: scroll-down to finish reading column 1, scroll back up to start reading column 2, and back down again, because you want to re-read the previous part of the sentence, from column 1.
So that's my two penny's worth of one-column favoritism.