I'm hoping this doesn't devolve into an argument about simplistic friction models..
Wider is gripper and won't breaking into a slide as easily. Should take a lil more effort to keep them sliding. Won't wear as quickly. And shouldn't heat up and get greasy as soon if you do lotsa powerslides, big hills. Next time you see a dude bombing a hill in SF check out how wide his wheels look, probably not on Classics.