Yes, I know, a little late, but I still use this computer and I'm bored, so here we go. - 14" iBook feels thinner. - While the 14" iBook and the 12" iBook have the same resolution, the 14" iBook has a bigger screen so text is easier to read. - The 14" iBook is easier to use because the keyboard isn't jammed up against the side of the laptop. - The 14" iBook looks better because everything (speakers, trackpad, keyboard) isn't crammed onto the surface. The 14" looks/feels comfortable and natural. The 12" looks/feels crowded. Feel free to add to the list.