Let's break it down:
Star Power
Star Wars: Mark Hammill, Harrison Ford
Cannonball Run: Burt Reynolds.
Hammill ends up typecast as a babyface his entire career, an unfortunate fact that he ended up rebelling against, culminating in that unfortunate appearance in Jay and Silent Bob Strike Back. Harrison Ford wasn't even the lead, and wouldn't achieve equal status with Hammill until after he was Indiana Jones. So when your lead gets passed by a supporting actor in the Star Power Sweepstakes, that's a problem.
Cannonball Run, on the other hand...Burt Freakin' Reynolds. All the women wanted to be with him, and, frankly, so did most of the men. He's Burt Freakin' Reynolds. Still making movies, while Mark Hammill is hiding out doing video game voices. Did I mention we're talking about Burt Freakin' Reynolds here?
Advantage: Cannonball Run
Fat Guy Sidekick
Star Wars: Chewbacca
Cannonball Run: Dom DeLuise
Chewbacca is even really that fat, he's just a big boy. Dom DeLuise, on the other hand...fat and funny. Captain Chaos? Hilarious.
Big advantage: Cannonball Run
Female Lead
Star Wars: Carrie Fisher
Cannonball Run: Farrah Fawcett
I don't recall seeing any posters of Carrie Fisher in a swimsuit with inadvertent nippleage. Plus...those buns on the side of her head? Really fucking stupid. There, I said it.
Advantage: Cannonball Run
Knights of the Realm in the cast
Star Wars: Sir Alec Guiness
Cannonball Run: Sir Roger Moore
Alec Guiness was a tremendous Shakespearean actor and all, but he's no James Bond. Roger Moore, on the other hand, actually is James Bond. Not to mention, he received his knighthood not for being a fine actor, but for his humanitarian work. That's got to count for something.
Advantage: Cannonball Run
Guest Stars
Cannonball Run: Adrianne Barbeau, Terry Bradshaw, Jackie Chan, Sammy Davis Jr., Jamie Farr, Peter Fonda, Jimmy the Greek, Dean Martin
Star Wars: umm...James Earl Jones's voice
Next.
Advantage: Cannonball Run
Actually, there is no next. I think I've made my point.