I saw a Shadow Blue car (not a Golf) at the dealer's, and it wasn't especially clean and it was a dull day. It seemed very dark, and I'd much have preferred a lighter shade.
But having said that, I'd go for it over any shade of grey/silver any day. There are just so many grey cars on the road. Maybe it's popular because lots of people like it but to me it's dead boring.
I went for Blue Graphite because the colour is more subtle than the basic navy of the Shadow Blue, though I suspect it will suffer from the same problem of looking dark in dull weather.
Grey/silver - sorry, just too common
Black - just a darker shade of grey
White - sure, if you wash it for me every day!
Red - too much in-your-face, and the red stripes on the nose are lost
So it had to be one of the blues, and I went for the more subtle one. But they're both too dark, in my opinion.
Having said that, I've never seen a Blue Graphite car, in sun or rain.
Rolfe.