Had a friend over yesterday who ownes HD600 ..... started comparing his HD600 to HD598, momentum, Shure, HD380, etc ...
His HD600 being the cleanest one (running from iPhone a 300 ohm can :-)
The HD598 in his opinion came close with some notes not being as natural as HD600 but definitely a bit more bass than HD600 ... (I think once he ads an amp, that bass would come back)
He really like Momentum for pop, dance, etc music on the go. Like ... really, really liked.
HD380 he felt was not as clear with high notes ... bass was the biggest but he said it wasn't too accurate. I start to see what he means again when you lower the volume to normal listening.
Grados he liked for some songs and disliked for others.
Shure he was cold to. Meaning ... not bad, not great.
I find that I am picking up the HD598 more and more and enjoying it more and more at lower volumes.
I'll be doing more comparison today.
My next purchase I was thinking about is Beyerdynamics 880 or 990 250 ohms. Problem is ... I think I can't get away not using an amp for those.