The AD2000 are dynamic headphones with a 40 ohm impedance unless I'm mistaken, so they're not a very difficult load. I would be surprised if the Anedio couldn't drive them very well. Pretty much everyone with easily driven headphones have raved about the headphone amp while people with harder to drive headphones (300 ohm and up) are giving mixed reviews.
Sorry for such a basic question but I'm very confused. I thought the lower the ohms/impedance the harder it is to drive the headphones. The Hifiman HE-6 is meant to be very difficult to drive and are rated at 50 ohms whereas the Beyer T1 is rated at 600 ohms and are meant to be easier to drive.