DAC upgrade suggestion


I am currently using a Audio-gd nfb 3.1.  The information below.  I bought a Topping DX7 pro based on the good data in audio science review.com.  When I first use it, I can hear the difference immediately.  It is more dynamic, bass is more punchy, sound clearer.  It sounds great.  But after listening for a longer time, I feel a bit fatigued.  I can compensate it a bit by switching the tubes in my amp.  Then, I need to return the DX7 because the Bluetooth doesn’t work.  I plug back in the Audio-gd, and i can confirm it is not fatiguing.  It is less dynamic, but also smooth.  Now, I am confused on what I should upgrade.  Several Audio-gd DACs are reviewed by AudioScienceReview.com and the data is very bad, LoL.  I know the bad data doesn’t mean it sound bad, but should I avoid DACs with good data?  How should I pick my next DAC?  It seems R2R DACs maybe a good choice for me since many people says the sound is more analog-like.

http://www.audio-gd.com/Pro/dac/NFB-2/NFB2EN.htm
gte357s
Forgot to mention, the Audio-gd has a in-house developed R2R chip, while the MHDT use an old TDS1541a.  Although the TDA 1541a has good reviews, but if Audio-GD do it right, a new technology should theoretically sound better.  And with the positive review in 6moons, I hope it means it is done right.  This is another pro to go with Audio-gd.
I will give my vote to MHDT Labs Orchid.

I have three DACs, the one I already mentioned and a Jolida glass FX tube DAC III and an RME ADI-2 DAC FS. I personally prefer the Orchid out of these, it's very smooth non-fatigue sounding in my system.

Just my 2 cents :-)
The Yggy is amazing - and it gets superb reviews, which rank it with the best available. 

But, the Dennafrips Terminator and Audio Mirror Trubadour also get superb reviews.  

All these are R2R Dacs, which sound much, much better than other types of Dacs.  

If you want sound, which competes with the best, these are the Dacs to consider.
I'm in the same boat as the OP. Just got a Topping D70.  It's definitely more detailed than my old MyDac.  However, I too, find it a bit harsh after a while. Maybe I just like bad DACs......
I have the Audio-gd R8 DAC and its a superb DAC for the money. You also have many setting options on the front panel and its FPGA programable wich can upgrade its sound with new firmwares that they launch about twice a year.

Ive heard three systems much more expensives than mine (just the DACs costed about 15/20k) and I prefered the sound of mine by far. Of course the whole system is important, but the R8 played its role with authority.

A couple of advices:

1-If you use USB from computer, upgrading your digital rig with an audiophile switch plus (like the Uptone Etherregen) a dedicated streamer (like the SOtM SMS-200 Ultra Neo) plus a good DDC (I have the Audio-gd DI-20) will upgrade the sound quality of your DAC to a compete with ones costing many more times. 

2-Dont pay attention to measurements, just your ears. My Line Magnetic LM-508IA 300B 805 valve amp has about 1% of total THD and my NC500 based class D amp (well regarded among audiophiles) has about 0.001% of THD. I prefer by a WIDE margin the LM-508IA, its a music monster. Much more realism, body, 3D sound and tone. Numbers are just that. You cannot guess the taste of a food for its calories. 

Finally, you can read a good review of the R8 here: https://www.hifi-advice.com/blog/review/digital-reviews/spdif-dac-reviews/audio-gd-part3/
In this review the used the older version of the R8. Now it has new DA boards and new firmware that rise the sound quality considerably.