I have an odac+o2 as well as the e5 and use my HD600 on both. Can't hear a difference between the two honestly. It's more about convenience with the e5 really (multiple inputs at once, PC + Phone) I take my e5 back and forth from the office and the other day I left it at home and my o2 ran out of batteries (don't have it on AC) so I was forced to use my onboard realtek. It was horrendous.
5/7/15 at 1:19am