I have both. Surprisingly perhaps, but the difference is big. Don't get me wrong, the HA-2 is not bad and I enjoyed it for a while. But... the Mojo takes things to another level. Things that it easily beats the HA-2 in are naturalness (realness of instruments), 3D soundstage (not just wide, depth and layers in the depth... amazing), lower noise floor, ... the list goes on really.