Is there a significant difference with an easy to drive IEM? If u use the E07K from a pc and a 16ohm iem like RHA Ma750 or Re-400 is it an upgrade over the iPhone4? Is the Fiio much better (mainly as a dac)? Worth to buy for home use? /pls dont describe the difference between a phone and a dac+amp... and dont compare with headphones, answer only who tried both/ Thanks!