WOW, that was a LOT of reading. I just read the whole thread from page 1 (about 3.5 hours worth), and am ordering a uS. My primary plan will be pairing it to my Verizon Note 3 phone (SM-N900V). I will also probably end up using it on Windows PCs at times.
Further, if this sounds as great as others feel it does, I may be grabbing a quality 3.5mm->2xRCA cable and plugging this into my JBL MS-8 that I've got in my e91 wagon, and just "muting" my music playback from my car's headunit, so that I only have the bluetooth audio and satnav instructions coming from my headunit, and then the audio playback from my phone running through the uS.
Thanks all for your contributions to this vastly informative thread.
Background: I own Sennheiser HD428, Logitech UE700 (a seemingly uncommon and discontinued IEM with 2 BA drivers per earphone), and recently purchased some Beyer DT770 Pro 250ohm headphones. These Beyers, purchased in August, required more oomph than any of my devices (phone, tablet, PC) could put out. So I picked up a FiiO E10 a few days ago, and WOW what a difference. I now sometimes look around when listening to music because I will hear something in the song that I've never heard before, or something I have, and it sounds as if the noise came from beyond the speakers. With the comparison I've read on here to the E10, I hope this impresses me as well.
I am also considering the FiiO E18, but as it is not releasing in the US until December, and at a similar price, I am choosing the HRT uS.
If I feel capable of describing the uS when I get it, I will post back with my feelings.