It's generally accepted as common knowledge that Horde players in World of Warcraft are, by and large, the more mature of the two factions. Whether or not this is actually supported by hard data is a matter of debate, but the logic says that older players are the ones best able to overlook the stigma of playing races long-perceived to be the "bad guys." There are mouth-breathers no matter what faction you roll, but perception is what it is.
We've been watching a poll over at Warhammer Alliance that sought to identify a specific age correlation between the two factions amongst the hardcore Warhammer Online community. With just over 2100 votes cast at the time of writing this, we did find an interest trend. Although Destruction was more popular than Order in every demographic, the disparity between the two become decreasingly pronounced as you move up in the age bracket. The ratio went from 1.7:1 in the 12-16 bracket to 1.5:1 amongst those 17-25 to 1.3:1 for ages 26-35, finally to 1.1:1 in the 35+ bracket. Does this mean Order will be the faction of choice for older players? Definitely too early to tell, but this early data is intriguing.