In terms of sound, I am extremely happy with the RNHP. But I simply cannot use certain full size with it, let alone IEMs.
There is a major noise floor issue for me, not like normal hiss but a clear chirping sound and a bit of hiss. With my AD1000PRM the chirping can heard clearly when not playing anything or at quiet passage, with my MH334, it is totally impossible to use with the RNHP.
Maybe using a switching power supply is not such a good idea anymore?