Jon Fairbairn
As one of the early Haskellers, I definitely preferred underscores, because my intuition told me that it was closer in appearance to normal English¹ text,
[1] and quite a high proportion of other natural languages.
Which makes me wonder - might there be a (natural) language bias as well? I'm sure most English-speaking people would have noticed that German tends to contain huge words from contracting adjectives and nouns that in English would be separate. (Cf. Daniel's example Anlagenmechanikermeister - it almost makes me wish for Germans to adopt camel-casing and making it AnlagenMechanikerMeister. In English, I guess it would be 'factory lead mechanic' or some such.) -k -- If I haven't seen further, it is by standing in the footprints of giants