I am also on the same way now...
My Glacier just arrived yesterday (
used). And on last week got back Headstage Arrow 4T (from repair 4G).
In the night for abour 2 hours I compared them. For arrow I used the Headstage USB DAC cable.
I use it with my "modded" SM3 v1 and with SGS3. Mainly have only FLAC and prefer vocal Jazz (and some mainstream).
In this quick compare I found the with:
Glacier (compared to 4T):
soundstage is littlebit bigger (around and deep/wide aswell, especially with my few binaural recordings),
sound a bit laid back (not problem maybe just for Glacier seems everything is just too easy to present) more detailed/refined,
recording mistakes more "visible" (for example none of the Red Hot Chilli records are adiophile quality),
well controlled sibilance, bass go deeper, and feels a bit more V shaped, good handling of complex music.
No EMI noise at all, just complete silence.
I don't like as this LED so bright and sometimes blinking???...should be at least 1/4 bright and size like on Arrow
4T + USB DAC Cable (compared to Glacier),
more lively presentation, feels just bit more dynamic and upper bass punchier, more focus on vocals (or this is balanced now?),
does not show too much details from the highs, a bit slightly out of focus, this means not shows record errors as honestly, some sibillance seems more "visible",
BTW in case of EMI noise (phone) this better than 4G, but very easy to hear...
I have a bit more than average trained ears, but the differences are really small to detect...maybe I am aging?
I tried the USB-DAC + Glacier as amp...clearly no go...but don't know which is wrong.
Direct SGS3:
Much small soundstage, deep bass and highs cutted, but the rest is balanced, good for average not complicated records, not so bad at all, fully ok for going outside.