Since this is a ladder match I feel a whole lot better about campaigning Punk over Vader, but even if this was a hardcore match Vader probably still wouldn't have won.
The rundown...
Drawing power - It's the Rock. if it's just straight putting asses to seats. But if you're one of those people that believe that working in the modern era where the WWE name brand is far more popular than any of its stars, and wrestlers appear before a world wide audience every week, then it's Punk.
Rock also had his hand in quite a sizable amount of marketing even before he left for Hollywood. Though I'd argue that he didn't truly become a household name until his acting career really took off.
Accolades - The only Punk reign I and probably most other people recall is his year and half long reign. That Rock ended. Rock's reigns were terribly short, but I still remember his feuds with Austin, and Lesnar, and HHH, and Taker, and Mankind. Punk I mostly remember his feud with Cena. Point Rock.
Longevity - This is Rock's biggest weakness. This point's Punk's. Even if he spent years in Cena's shadow he was still #2.
Consistency - Punk didn't headline PPV's while champion. Point Rock.
Charisma - This is where I'm split. I never really liked Punk's wrestling style, but as a talker I was always enthralled. Rock is probably the greatest actor in wrestling history. But as an actor his lines often didn't sound organic. Like he was always reading off a script. Nowadays that's pretty obvious. The average Rock promo was cheap pop, curse words, talking about somebody's rectum, catchphrase, more curse words, some sexual innuendos, another catchphrase, another cheap pop, more curse words, and then a catchphrase to finish. Punk had great dexterity on the mic and he always felt genuine. Rock may was well be a slogan machine.
As far as saying one connected to audience better than the other, I'd probably go with Rock since he was better at putting butts in seats.
In ring ability - It's subjective but I'd probably say Rock. Though Punk has his fans and that's fine.
Lasting legacy - Punk has likely hurt his legacy after jumping to the UFC. Maybe he didn't. We thought Rock hurt his after jumping to Hollywood a decade ago. But even to this day his still remains one of the WWE's biggest stars and broke down allot of racial barriers in the process. He wasn't the first Black champion, but he was the first to be a big era star.
Ladder be damned. Vote Rock.