Arnold easily.
Yup.Better than the first Rocky?
Yup.
Sly has the better franchise with Rocky, but most of Sly's films outside of the Rocky & Rambo series are
This. Arnold, surprisingly, has a more of a variety of filmography and actually has range.
Rocky is not only sly's best movie but IMO it's the best from those 2, and he wrote it. He was also nominated for best actor and best screenplay, Arnold ain't never sniffed a Oscar nomination.
Arnold has a better catalogue of movies he's starred in, but sly actually writes and directs.
If we talking better movies, than it's Arnold. But if we talking acting, I'm taking Sly because of Rocky and to me Arnold never impressed me as an actor.