Your right but having heard the iBasso DX90, the Fiio X3 II and X5 II, ZX1 and more recently the ZX100 I prefer the sound of the DX90. Not just more power but better detail, bigger sound stage etc.. Check out some of the DAP rundowns for 2015 and you will find reviewers rate the DX90 and Fiio's 2nd gen X3 and X5 above Sony's DAPs for sound quality, not just my opinion. Only reason I never bought the DX90 was it was not available for sale in Canada when I was looking to buy a DAP and it was out of my price range as the ZX100 is now.
I can agree on everything that you said about Sony Daps. if you will read back on some of my post here you can also see that i criticize Sony Dap
They are not perfect, Fiio/ibasso has more feature than Sony. i even said that i have more cons than pros on sony Dap.
- no screen protector , other brand have 1 already attached + 1 more free
- ZX100 no free case, zx1/zx2 have. other brand have
- no line out
- cannot use as desktop dac+amp
- screw data cable
- expensive case/accessories
- ZX100 not touch screen
- no wifi support
- ZX100 primitive OS
+ majestic battery life
+ good SQ
+ easy to use OS
+ Ok button design/layout
things just narrow down on what you really need and want on a Dap. if you want touch screen then look for a touch screen Dap.
a couple of months ago i almost bought the DX90 2nd option is the Fiio X5 2nd gen, but i didnt buy them because of reason
DX90 = terrible battery life, some reports only 6-7 hours, for me this is very unacceptable
Fiio X5 2nd gen = i dont like the wheel button. yes! that Da*n wheel button
DX80 = new model, i already expect the FW issues
Fiio X7 = over the budget, $600 above??..
I bought the ZX100 because it is way cheaper here in my place less than $450.
Dx90 or Dx80 or Fiio X5 2nd gen + 128gb card = will end up the nearly $450 here, same price with ZX100.
there is no prefect dap, in the end just buy what you want/like