Hugh and
Hugo are more or less interchangeable to me as far as aesthetics and all are concerned. They may as well be the same name because my feelings on them are just about identical.
But I still think there's something more "usable" about
Hugh. Maybe it's because of
Hugh Grant (God help me, I love
Hugh Grant) or something like that but it seems more... well, usable.
Hugh reminds me of a list of names that I have mentally designated "not quite" classics like
Graham,
Ross,
Reid,
Leo,
Colin, and so on. Solid names with a long history of use but just not in the same place for me as
William,
Michael, etc.
I don't know what it is that makes
Hugo less friendly in practical application. It might be that something about Latinized forms being almost... archaic? Well, not as extreme as that but still "old" sounding. And of course even then not in all cases. But at least with
Hugh vs.
Hugo, I do get an older and maybe mustier feel from
Hugo. IT does not have the more "updated" sound to me.