Objective performance perhaps. I still preferred the HD-650 from the Valhalla 2 out of the Mojo, but the Grado RS2e sounded better straight from the Mojo. But as I'm currently selling the Valhalla, it's not a big enough jump for me to justify keep it. So I'm selling some stuff to buy a better headphone (Elear). I suspect the Mojo will drive it well. If I still had my Torpedo III, I'd uneqivocally prefer that, but it boils down to personal preference. Driving straight out of the Mojo is the most "purist" approach.