> no deep standby (box warm, power intake way over the EU limit)
there is deep standby just press and hold power button (did you measure in deep standby?)
> no DTS passthrough over optical (while having video via HDMI)
never used that don't know
> stuttering, choppy 1080p 60fps playback (camcorder files .mts, .mp4) -sound breaks after 15-60 sec
never had such files, but seems to be a issue on all sigma players.
> high bitrate movies make the box crash randomly or the playback suddenly just breaks (same movie plays with no issues on Samsung/LG smart TV or a Realtek player)
i never had a crash with my movies (mkv,avi and bd isos)
+ other minor issues with subtitles and resuming playback - not fixed.
i don't use normally subtitles, but where i need them they work