I'd say Vader. Anakin made rash decisions (became a torso lump on Mustafar) and Vader has more experience. Sure, Anakin has raw power but he's an idiot. I think he'd make a mistake and Vader would capitalize.
It's a bit of a tough one, though. Vader has had Jedi fighting experience via post O66 clean-up and Anakin cleaned house at the Coruscant temple. Let's face it, though. It was mostly younglings.
I wonder how Kit Fisto would do against hundreds of those...
Bah, nevermind.