I am a Seattle fan and think the XLIX title should be vacated, which means no one wins.
Seattle didn't earn it, so it shouldn't be handed over, just vacated. This "punishment" won't deter teams from cheating if they get to keep their titles after said cheating occurred. They do this in college and even the Little League World Series.
Good Gawd how I hate Darrell Bevell (Seattle's epic fail of an offensive coordinator), hand the ball off to Lynch and Seattle wins!