]Kris Benson: Career Winning % .483, career ERA+ 103 Victor Zambrano: Career winning % .530, career ERA+ 101. For starters, winning percentage is just about the worst way to judge effectiveness. So career winning percentage can be ignored. For seconds, well, Benson is a better pitcher. This argument is weaker, but I'd be willing to bet that Benson has a better year. You can pick pretty much any category you want to judge the word "better".