Much like the difference in opinions on the HD800, I find the recommended amps also in opposition. I know I'm a bit out of group consensus on this one. Like everything I suppose it's what you want to emphasize/minimize and your source. From those I've spent significant time with (most owned)... BA 2A3/BA AD1 > Peak & Volc/S7 > Arete & Volc > Peak SPU/Arete SPU > DSHA-1 Proto > P1 > P1u > B22/Another B22 Basically, I love the BA and Peak with it, though never heard the GS-X MKII or production ECP... or Pinnacle / Teton.