Classic creates the same density, but is less finicky in achieving it. Under optimal conditions, New produces virtually the same prints but with potentially a little less staining, and from a negative with a much, much larger density range.I like the deep blue of New Cyanotype
I did cyanotypes quite intensively for a while and I have several prints from a period when I went from Classic to New and I can't for the life of me tell today which process was used for which print. They're indistinguishable.

whatever works! It glows!