Abstract. There is rapid growth in the number of IPv6 users and IPv6 compliant services on the Internet. However, few measurement studies exist about the quality of user experience on IPv6 in comparison to IPv4 for dual-stacked hosts. We present results from a measurement trial consisting of 21 active measurement probes deployed across Europe and Japan connected behind dual-stacked networks, representing 19 different Autonomous System (AS)s. The trial ran for 20 days in September, 2014 and conducted two types of measurements: a) YouTube performance tests and b) Speed tests to nearest dual-stacked Measurement Lab (M-Lab) server, both over IPv4 and IPv6. Our results show that a disparity exists in the achievable throughput as indicated by speed tests. We also witness disparity in content delivery servers used for YouTube media for some networks, resulting in degradation of experience over a specific address family.