Wow, it does look nice. I usually don't pay that much attention to Fiio because they are generally below my price point (all though I respect them as a company for what they have done for the audio industry). However, in the real world I design outerwear, and I really like the look of the Fiio E18. It looks like it might be priced a bit higher than previous Fiio DAC/amps which is why I am excited for it.
No prob man. If you're considering using the Leck as a desktop, you might want to look into getting something that either converts USB audio into digital coax, or just use a source that outputs digital coax-- I believe it does 24/96 from S/PDIF, and supposedly sounds better to boot (haven't tied it myself). There are some portable USB-to-S/PDIF adapters that are around as well in case you want to do 24/96 on the go, but I haven't tried any of them. And my comparison is here-- be warned, however, that I have never used two words when twenty would suffice ;).
I'm also very interested in the D-Zero SE-- I think the D-Zero frankly kicks everything's butt from a value-for-money perspective. Killer little device.
As for the DragonFly, I believe some people have had success with a few of the USB-powered DACs by using special splitter cables and a portable power source, although I don't recall if it worked with the AQ DF specifically. The only time I tried to use a portable battery (a Monoprice dealio), I got a lot of noticeable noise on the line, so I dropped it pretty quickly-- but others have had better results, I think.
As for sound quality, a couple of brief qualifiers: the only actual A/B comparison I did was with the PCSTEP and the Glacier, and my tastes drew me to the PCSTEP; I apparently listen at unusually low volumes, and prefer a brighter sound signature; I am in absolutely no way whatsoever an audio professional of any kind; and while my musical tastes are varied to say the least, I tend to listen to more dissonant music (metal, some classical and string groups, some jazz) and atypical time signatures than your average bear. So keep those in mind. But in general, I believe I lean a bit more towards the Leck and Meier than the Glacier, and while I love the D-Zero, I think those two are a bit more clear and neutral.
Hope this helps! Search the forums for used devices, as the Leck, Meier, and Apex tend to hold their value pretty well IMO, so you might be able to try a couple of them out without losing your shirt in the process. That's how I got my Glacier ;)
Your opinion seems to be inline with what I've read. The glacier has a beautiful form factor, but its DAC (while not bad) aren't any thing spectacular for the price point. It seems like the sweet spot is ~$300 for portable DAC/amps and I'm more than happy to spend that much. I tend to enjoy a neutral sound signature as long as the components in question are very good (I EQ my car a bit because it doesn't have the best components in it). I've also been waiting for the iBasso DX50 to come out as a potential upgrade for my portable rig, but I've been leaning towards consolidating my phone/portable DAP. I think I'm going to wait a few weeks/month(s) to see how the iBasso D Zero-SE, and the Fiio E18 fair against the above DAC's.
Thanks for everyone's help! Being an audiophile would be so much more expensive/time consuming if Head-Fi wasn't such a great place!