After reading and listening to both these talented musicians, I would have to go with Van Halen. Everyone has mentioned that Rhoades knew music theory, that he's slightly better and he played far more difficult music. However, no one has mentioned the fact that Van Halen was a classically trained pianist which in a way formed the basis of his music. After taking his music and translating it from tab to the piano, some of his solos could easily be mistaken for classical music. Van Halen influenced rock guitar more, lets face it by mixing a modern sound to the influence of older music. Anyway, Van Halen could play more than just heavy metal, which seemed to be rhoades restriction.