It does have more powerful output than WM1Z. But the one thing I do not like about the GT is that it uses too much DSP for playing back PCM, where as the WM1Z does not. The warmth and analog from WM1Z comes from it hardware genuinely, while the GT comes from all the DSP. So, the question would be authentic ? Or artificial ? To me the GT has a similar analog and warmth signature but with very different approach, in a way that render the GT with it own uniqueness that is by itself.
I later found out about what hardware were put together to build the GT and it only further confirmed my findings from a combinations of : GT own DSD engine, DSD file, PCM file, critically listening , analyzing hardware.
Another thing to note is that GT uses Ribbon Cables internally, and the 1Z has the Kimber Cables. For the same pricing bracket, and if you understand what any quality internal components should look like that is dedicated to music, the 1Z would laugh at the GT
Yes, one can argue that GT uses Black fin DSP chip and their own OS with AK4497EQ. Well! WM1Z uses Sony unique proprietary DSP chip, and Walkman OS, S-Master HX. There really is no hardware and engineering competitions here between the 2 devices.
It will all come down to your preferences, so you will have to judge them both side by side and for yourself with your favorite track and headphones or ear buds. If I was to pick something that isn’t a Sony, I would pick Ibasso DX220 which I do have, but if I had to pick something more expensive with better built, I would Pick Cayin N8
That is my own opinion