I have the new NX4DSD, sounds awesome to me, I use my old oppo find 7 with it, and my xioami mix. It sounds great with the xioami pro HDs and even better with the 1more quad drivers. I never realized how much the bass was accentuated in the xiaomi mix, to the point I thought the quad drivers were crap, I thought something was missing in the mids. Once I put them together all frequencies evened out. I only use maximum a quarter of the volume knob, I'm sure that more than that would blow up my ears or the IEMS. I looked at all the options around the 800RMB area, and waited for the 11.11 discounts, since i preordered it, it was only 830 now its a 1000rmb. My other options where the FIIO Q1v2 or a dragonfly but i gave topping a chance on my previous use of a sabre ES9xxx.
I'm pretty satisfied with it, to the point I'm now thinking of changing my desktop setup because it sounds like crap compared to the topping+quaddriver combo. I actually believe these guys are OEMs for several high end manufacturers because the soldering in the board is too neat for a small builder, but what do i know....
Edit: forgot to mention but i does get a bit hot to the touch, but i think the aluminum enclosure is dissipating the heat, some people have told me that the chip used in the topping NX4DSD might suffer audio degradation if it gets too hot, but i haven't heard any problems yet.
