You'll see my review/comments way down at the beginning of this thread - I did finally get my issues resolved and received an MK2 as a replacement for my original unit. Oddly, after finding the original one buried under some junk in my office I plugged it in and it started charging again...
That said, quality issues continue to plague these little amps and they are tempermental to say the least. When they work, they're fantastic, but only *when* they work.
The problem I have with the MK2 is also revolving around the battery. I can leave it plugged in to charge until it says it's fully charged, link it to my phone and it will show 100% battery, then as soon as I unplug it, the battery will drop to anywhere from 65 to 85% (the Battery saver setting is *not* on). On a recent flight to California from the east coast, I was down to about 15% battery on landing which means it didn't last but 5 hours, which is well outside claimed 14hr life and much lower than my original unit.
I in-fact had my original unit with me as a backup, and turned to that unit for the return trip and it worked flawlessly - showing 100% battery on and off the charger, lasting the 8-hours of travel (had a layover) with battery to spare.
And to assuage any concerns that I mixed the units up; I had changed the LED on the MK2 to white the instant I received it, something you're not able to do with the original.
I really do want to love these because they work so well, but they really need to work out their QC issues. The companion app is incredibly robust and has never given me an issue on Android. At the full $100 bucks I have trouble encouraging the spend. $85 is still quite a risk but it may soften the blow if you get a finicky unit.