In this video as part of the Motley Fool's "Ask a Fool" series, senior advisor to the Motley Fool's Rule Your Retirement service Robert Brokamp takes a question from a Fool reader, who asks, "If you had the option to invest in a traditional 401(k) or a Roth 401(k) which would you invest in and why? I have been contributing to a non-employer matching traditional 401(k) for years and now I have the option to also start a Roth." Robert breaks down who benefits best from a Roth account and who would be better off sticking with the traditional 401(k).