I've been doing some tests this evening (and still am doing actually!) 'cos I haven't really been happy with my speaker setup (Marantz DV9500 -> unbalanced RCA -> Accuphase E-407 integrated amp -> bi-wired/bi-amped -> B&W Nautilus 804 (aka N804). I've had this setup for more than 12 years (the Marantz DV9500 came in around 2003/2004) and probably thanks a lot to headphones, I found my system lifeless, uninvolving, lacking detail and basically sounding "flat". So I've been demo-ing other higher end speakers, tried removing bi-amping/wiring, and finally changing my source.
In goes the DX100 lineout to RCA (again unbalanced) compared to my 9 yr old Marantz DV9500 and surprisingly the DX100 seems to be outperforming the Marantz SACD player - this is even comparing SACD vs 24/192 on the DX100. The DX100 increases the soundstage more somewhat and is beginning to actually feel more immersive.
I know I shouldn't be thinking it's just merely the DAC chip difference (ES9018 vs Cirrus Logic CS4398) but it has given more more faith in the ES9018 that I'm out looking for the Oppo BDP-105 now to replace my DV9500. Kinda says quite a bit that the DX100 playing 24/192 can outperform a proper speaker rig SACD player. Admittedly the DV9500 isn't a top end SACD of course but at the same time I didn't expect a portable to perform that well.
P.S. I'm comparing it against the MBA -> USB -> Benchmark DAC1 Pre -> XLR -> Accuphase E-407, and I'm
still leaning towards the DX100.
[Edit] Correction, the DAC1 Pre balanced feels "fuller".