This paper examines the practical usefulness of two new journal performance metrics, namely the Eigenfactor score, which is said to measure “importance”, and Article Influence score, which is said to measure “prestige”, using the most recent ISI data for 2009 for the 200 most highly cited journals in each of the Sciences and Social Sciences, and compares them with two existing ISI metrics, namely Total Citations and the 5-year Impact Factor (5YIF) of a journal. It is shown that the Sciences and Social Sciences are different in terms of the strength of the relationship of journal performance metrics, although the actual relationships are very similar. Moreover, the importance and prestige journal performance metrics are shown to be closely related to the two existing ISI metrics, and hence add little in practical usefulness to what is already known. These empirical results are compared with existing results in the literature.