I've had a play with the audio features now and first off HTC U Sonic is amazing, the thing where it scans your ear canal and sets up an audio profile. On the result page it plays an awesome tune which I'm trying to find to add to my music library, there is also a toggle where you can turn U Sonic on and off in real time so you can hear the difference.
The headphones are USB-C so they plug into the same port as the charger and there is a USB-C to 3.5mm adaptor in the box if for some reason you don't want to use the Sonic earphones.
For anyone pitting this against the Samsung S8, my brother bought one, I'll make some comparisons. The HTC U11 is wider and taller, about 4mm each dimension and it's thickness me and my brother agree is the same. Despite the difference in vertical height the S8 has a bigger vertical display . The S8 isn't as ugly as it looks in photo's but personally I'm not keen on the edgeless sides curving the display, if you look at the phone side on you can see the curved display but it's just light so it's kinda redundant, it's kinda like a letterbox film effect. The back of the S8 is nothing special, almost completely flat like the U11 except for a small ridge around the camera. The U11 has the liquid glass mineral finish.. basically it's pearlascent and a mirror.
I'll see if I can nab it later to try and ascertain UI speed, any lag, sound differences.