I'm using it with AK120.
Burned them for 150 hours (50% of time with IsoTek + 50% time with TaraLabs, at volume level a bit more than usual level).
Sounding 8/10 for me: detailed, lots of quality bass (even with EQ off), good scene, good separation of instruments, airiness.
Sounds distinctively better than my stock D2000 (despite opinions of
LOTS OF "professional" TROLLS on this forum).
But heavy genres are better with D2000... (heavy / thrash / death / melodic death)
D7100 is far more genre-universal: classical / jazz / light rock / electronic / pop are just great with them.
But metal sounds somewhat less agressive and more "intelligent" than on D2000.
Cons:
- lack of recording quality is
quite clearly hearable with my setup (AK120 + D7100).
- vocals somewhat recessed in relation to instruments. Still can be improved by EQ.
- design (it's not perfect for me, though, not fatal on the other side)
- sits on my head unreliable (no sharp movements with it!

On the other side, sits very comfortable.
AK120 is even less forgiving: it both musical and analytical (detailed), so much less tolerant to bad recordings VS ipods/iphones.
Got them for $830 back in November. Definitely worth the minimal price tag of $600-700, not less (!)