I have been mulling over this DAC for a couple weeks, and I do not think it is definitively better than the Topping D70 Pro Sabre even from a purely objective sense.
My argument is simple:
While the D90 III's SINAD on its own is a smidge better, 123.8 dB versus 123.4 dB....
....the D70 Pro Sabre beats it in several other important areas including:
1. The D70 Pro Sabre offers an impressive 23 bits of distortion free range with a 192 Khz 32-tone multitone signal versus the 21.7 bits of the D90 III.
2. The D70 Pro Sabre offers lower distortion (flat across the audible spectrum) with its default filter, versus the D90 III which has a visible rise above 8 KHz.
Add to that that the D70 Pro Sabre has a spectrum analyzer and beautiful color display and interface. Subjective, yes, but consider this. Suppose you are presented with these two DACs, one with very, very, very slightly better SINAD while the other has a bit better multitone and filter distortion/noise performance. Then this other has also a modern user interface which is a huge plus over the blatantly 90s digital alarm clock design of the flagship. Suddenly, the D90 III really isn't that compelling and maybe even shouldn't have gotten the flagship pricing treatment.
Indeed, the D90 III has a technically world-class SINAD but Topping really needs to stop playing this one-trick-pony game of SINAD. Otherwise, they will lose sight of other key objective measures and other extremely important features in I/O and UI that users also value. And before they know it, they will get passed up by competitors like up-and-comer EverSolo who has truly upped the ante in integration, I/O, and UI.
As always, feel free to correct me. We are all here to learn and have fun together!