We will not have all the answers until it has been reviewed/measured. Here are the downsides we know on paper (G6 | X3)
Dynamic Range: 130dB | 115dB
Max Playback Rate: 384kHz | 192kHz
Specified rang of output impedance: 16-600 | 32-600
What does this mean? We don't know. I won't notice the lower max playback rate...
What we do know, this is based on the SXFI. That has settings specifically for the Philips X2. I would be surprised if the mobile version supports the X2 but the desktop version does not.
I did order one, and will compare it to the Fiio K5 Pro when it comes in. Assuming I don't cancel it and just get the D50s/Atom combo.
Note: I have a X2HR.
Update: I decided to cancel my order for the X3. I decided to go with the safe bet JDS Atom + Topping D50s.