I used the A10 and Zo2 on my commute, and can tell you that the A10 had a lot of trouble with EMI
My Zo2 dual locked, barely has any, and when it does, it's not ear piercingly loud like the A10's
I put my D2K's in my room (quiet environment) and could tell the E11 had the loudest hiss, almost as loud as the E5 had.
A10 cam after that with barely any hiss, and then the ZO2 with the very slightest hiss.
All plugged into my phone and PC for the same test + 2 way splitter to make sure.
How do you compare the E5 and E6?
If you own the E5, might be worth putting it in the list :)