Don't agree with either statement. Guice is not 240lbs.-250lbs backs like Lynch, he is more similar to Marshall Faulk with a second gear that can run away from defenders. Lynch never ran away from many, at any level.
Fournette is a unique physical talent, there aren't many kids coming out of college that are 6' feet plus and 235-pounds with 4.4 speed to run away from a defenders, over or through defenders. Now he may not have a long career in the NFL like Petterson, but he has similar ability of OJ Simpson, Chuck Muncie, Bo Jackson, Herschel Walker, Earl Campbell or Eric Dickerson. The list is very short over the past 30 plus years of college football. He is a freak athlete.