Not being a morning person I would much rather have what little light there is in the afternoon. I seem to recall hearing that the road-accident argument favours more light in the afternoon as pedestrians and drivers are more tired than in the morning (whether it's dark or light) or something. I wasn't interested enough to make a note of the source of the stats for that but I do think that this argument is one of hte most important ones - children going to school or coming home in near darkness isn't good really, and it's worse in Scotland of course.