My guess is that the 802/901 will sound fantastic but operate at lower voltage and thus have more compact battery and reduced voltage-swing output, though with similar low impedance in order to drive CIEMs properly, as standard.
I anticipate 10-12hr battery duration.
I don't anticipate the 802/901 outperforming the DX100, but rather *almost* performing as well as the DX100, whilst having more compact dimensions, better battery life, and slightly cheaper asking price. I also suspect that many DX100 users will end up buying an 802/901 as a companion to the DX100.
This wouldn't have been the scenario with the 801 as it had too many downsides to justify being bought after a DX100, but if the 802/901 is as user-friendly as I'm anticipating, it may well be tempting enough for existing DX100 owners to add to their portable DAP arsenal.
Only time will tell...