The DMP-A6 is quite an attractive unit, very tempted to buy one. In looking at the DMP-A6 forum page at Zidoo, there are a few red flags that would stop the purchase.
USB DAC compatibility
There's no guarantee that your DAC will work with the DMP-A6, primarily being based on Android. 99% of DAC manufacturers can supply a Windows driver if necessary, but not necessarily Android, this comes into play for native DSD support.
Getting hot
Under certain conditions, the DMP-A6 can get too hot.
Use of a modified Android OS.
Should 'the best' player become available since sliced bread, the OS in the DMP-A6 may be too old to work with this modern marvel.
Airplay2
I don't use, but it looks like AP2 is on hold for the moment.
I'm looking for a DAC in the office system, and thought the streamer would suffice, but not the case. Audio-GD have some interesting NOS DACs, might give them a shot.