OK...is hiby R6 the end game DAP? No..there is no such thing as an end game audio device and we all know that :) but R6 comes very close.
Do you need any other DAP, portable DAC, amp etc after buying the R6, NO. This does everything I throw at it. It can handle all iems I have tested so far including the tin p2 which requires a ton of power. R6 drives the hifiman Sundara and also the HD650 via balanced!!
I started selling my portable dacs after buying the R6 as I don't need them anymore. I only use the headamp pico now along with R6 to drive power hungry HPs as I don't want the battery on R6 running out.
Now coming to sound quality, by default it's tuned to be more detailed, punchy bass and crisp treble. So a bit colder but this is because R6 has an amazing settings app called the MSEB which you can increase warmth, bass, etc..I can't stress enough how useful this is :) I can make almost any iem and headpone the way I like it to. Trust me, you will get addicted to this.
Battery life is amazing, looks pretty, sounds great, drives all iems and HPs, enough said. Just buy it and you won't be disappointed l.