well i also belong to the big head club... so my issues are the same and was suprised to learn there really is little to no battery in the unit itself as noted above. real time trickle down in seconds when using high brightness as a test.
my arm also arrived broken(the final piece that connects to the cinera was in three parts in the box? (failed weld of the tension ring?) as it just flops around on the ball joint.... I will be filling a requuest shortly.
The experience is pretty amazing overall. I spent the day testing UHD rips from my library until i got down to a file size the unit will play natively without corruption/loss of quality. around 12 -16 gb depending on the audio quaility selected. some may find this annoying but in my use case that is perfect for portability with variety. I will use it hooked up to a nvidia shield or my pc when home so no issues playing uncompressed rips locally or through plex on the shield.
I am unable to judge 3D as I have a lazy eye and see almost no 3D anyway. I have tried headphones via 3.5mm jack and bluetooth and no issues with BT lag at all.
as far as gaming goes it's a mixed bag until i have a fully working arm comfort wise, but i played a wide variety of game types and other than CS go(which ran lag free) FPS is the only genre where input lag is fairly obvious(as on the ps4 1st run) but everything else is really awesome civ6 is playable and text is readable without issue at full resolution.
I saw a negative review re: anime with subtitles. so, i tried a few and am not sure what their issue was, no issues here with sources all the way down to 320p. top or bottom the text was readable and clear. but, to be fair I am using english text not Cyrillic or Asain fonts so your experience may vary.
let me know if i can address anything else.